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Fuel Pressure Regulator ?

38K views 85 replies 7 participants last post by  WilliamE 
#1 · (Edited)
I have a 96 Buick park Ave, Base VIN K

I have had on and off chuggle issues, and problems starting the car after driving somewhere, sitting, and trying to start it back up, for example going to Walmart...

I replaced the fuel pump, CKP, TPS, cleaned the IAC, MAF, replaced the ICM, and a failed coil pack, and just found out I have 6 wet/fouled plugs.

I had a mechanic test it, and say it had low fuel pressure, which is why the fuel pump was replaced, he said it had the right pressure after that, I am not sure I believe him.

I went over my AllData manual, and found out how to remove the FPR, I cleaned it up a bit, cleaned the screen with gas, it was a bit dirty, I noticed a little yellow caked sentiment in there where the FPR seats, so I blocked the hole to the fuel rail inlet and cleaned that out, I then removed the O rings, cleaned and lubricated them with clean engine oil.

When I put it back in, keyed to on to get the FP up, then disconnected the batt cables, and held a towel in front of the schrader valve, and granted I had no fuel pressure gauge, I could see at least a 25-35% gain in pressure, it rushed out of there, when before it pathetically squirted out.

I'll get me a fuel pressure tester ASAP, but my question is this, if that FPR had problems and was limiting pressure when engine demand increased, is it possible that is what fouled my plugs out, and led to a start, run a second or two, then shut off condition.

NOTE: I am sure it is not a security issue, my injectors have 12v, they just were pulsing very weekly..

I do have a PCM programmed & on the way in case the PCM had a circuit go bad in it, but now after seeing the fouled plugs, and the increase in pressure from cleaning the FPR, could I possibly be on the right track as to solving my injectors not pulsing issue?

http://twabbler.net/images/47885332503245858955.jpg
 
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#2 ·
low fuel pressure will not atomize through the injectors properly and will flood the cylinders.

I always tell people to put a check valve inline about 6" behind the firewall on the hard line then run AN line from there. it's easy and damn near always solves the problems.

Drop in fuel pumps for our cars have bad check valves a very large percentage of the time. the FPR is cheap and easily replaced.

Also make sure the injectors aren't stuck open.
 
#3 ·
So it is possible the pressure being too low is what helped foul my oem AC Delco Iridium plugs in only 50,000 miles, or is that fouling normal?


Are you saying it would be good to have a check valve other than the schrader valve to check pressure at?
By the AN line I assume you mean the steel flexible fuel line?

Forgive me for not knowing correct terms for everything, I am learning, which is why I ended up here, I deemed it the best place for help. :)

As for checking to see if they are stuck, I did a few tests, each has 12v at the proper wire, the ground from injector to PCM I was not able to test for continuity, I still need to find which wire it is at the PCM harness, I did however check resistance of each injector, and I believe each was about 11.80, I'd have to check as it has been a few weeks since I tested them.

I was told by the mechanic that he could spray fuel into the TB and it would run, the injectors just had a very weak pulse..

Is there a better way to see if any are stuck open?
I did put some Seafoam in the gas tank, and a little in the crankcase, but this was because I had bad idle problems, and then got a cylinder 3 misfire, so I replaced a coil pack, it ran beautifully till I got home & let it idle for a second, then cut the AC on to see if it still cut off like it was when doing so before, and then it died totally.
 
#5 ·
I'm sure they were, and still are AC Delco Iridium, I put the last ones in myself around 50k ago, and I just replaced them again.



I may look into getting a check valve installed ASAP, I got my programmed PCM, and I still was not able to get the car to run, so I am pretty sure my FPR is still good, but due to issues I've heard with them failing & causing the intake to get a hole blown in it, I 'll go ahead and replace that when I get the money.

I removed my fuel rail the other day, and the little pinholes look clear at the tip of each injector, to the best that I can tell, once I put it all back together I'll see if they all spray fuel properly.

I am in the process now of replacing my upper, and lower intake manifold gaskets, as well as the EGR gasket that has the screen..
Due to things that I experienced before the car died, and due to visual leak around the UIM, and caked up oil all over the oil and transmission pans, and the fact I was loosing coolant rather quickly, while gaining oil, I'm pretty sure my engine is hydra-locked.

I may need help with things along the way, since I've never done this before, so I'll probably create a thread in the proper section.


Thanks for the response imp0ster!
 
#6 ·
Hydro locked engines usually always bend a connecting rod, destroy bearings and ruin the pistons. Fluid doesn't compress :(
 
#7 ·
Ouch, good to know, thank you.

Do you know if a engine is hydra-locked can you spray starter fluid in the throttle body and have it run without a problem?

I am thinking no, but want to be sure.
 
#8 ·
You will need to run a compression check on every cylinder. Anything under 105 and its dead.......bent rod.
 
#9 ·
Thanks corey, is there a certain compression test kit you recommend?
Here is one I considered getting, if there is a cheaper one that would work as well I'd rather get that though, as this is not something I'll be doing on a regular basis, maybe at each plug change...
http://www.amazon.com/OTC-5606-Comp...TF8&coliid=I29GOBX22IVCF2&colid=3CY05SRJTA776

Doing the cold compression test is fine right?
It is all I'll be able to do since the car will not run, of course that may change when I am done with the LIM repair I started.

Do you know if an engine is hydra-locked can you spray starter fluid in the throttle body and have it run without a problem?
I ask because the mechanic I went to said it would not be hydra-locked and run, he also said he sprayed starter fluid in the TB and it ran fine.
 
#10 ·
That kit will work fine. The engine may "run" while you are spraying it but it really wont tell you much. Its not something you really need to do to diagnose your problem.

Hook up the kit and crank the motor over 3 or 4 times (2-3 seconds). You will want to take most, if not all of the plugs out to get a true reading.

Hope this helps, post your findings so we can try and help further.
 
#11 · (Edited)
I've never done a compression test before, but I watched a few videos, and am pretty sure I can do it without a problem.
I just think I may need to get a little oil can, and maybe a little pvc hose, that way I can do a wet compression test as well as a dry one.
I'll unplug the wiring ti my ignition control module, and remove the fuel pressure relay.

Hopefully this one is the one will work well also, I have it on order.
http://www.amazon.com/gp/product/B00020BM28
It is a bit cheaper, which is better for me considering money is limited right now.
I'll post what I find when I get it tested.
 
#13 ·
I agree with coreyt83. The wet compression test is primarily used to check piston rings, and that's not your main concern right now, and chances are you're never going to be concerned about the rings. You're looking for a possible bent rod, so you're simply looking to see if one or more cylinders doesn't hold compression.
 
#16 · (Edited)
Still waiting on the compression tester to get here, it is said to arrive Friday.

Just curious, but if a rod was to bend, if I were near the engine when it could have happened if it did, would I have heard something?

Because it died slowly, and rather quietly, I was standing right in front of it when it died, I turned the AC on, walked to the front, & the idle got bad by the time I got around the front of it, then it cut off for good.
It was like it was being starved from fuel, a mechanic did tell me that the injectors were not pulsing, I checked everything I could, the injectors could be clogged I suppose, I just assumed Hydra Lock because of the extra oil I seemed to be gaining, and the antifreeze I was loosing that I could not account for.
 
#17 ·
Compression Tester arrived early, and I removed all plugs, and tested each, giving each 5-6 rotations.

2) 105
4) 100
6)105

1)105
3)117-120 :/
5) 97-100

I tested cylinder #3 three times and it was from 117-120, I expected to have trouble there if any, since I got the cylinder #3 misfire code a while back.

What should I do now?
Any help is greatly appreciated.
 
#21 ·
2) 105
4) 100
6)105

1)105
3)117-120 :/
5) 97-100

I tested cylinder #3 three times and it was from 117-120, I expected to have trouble there if any, since I got the cylinder #3 misfire code a while back.
Cylinder 3 is your only good one. 1,2 and 6 are boarder line. 4 is dead, and 5 is most certainly dead.
 
#18 ·
I was told by a friend that those numbers sound ok, and I should put it back together.

So I'm wondering what is stopping my fuel from being delivered through the injectors, I was told the fuel pressure was right when the mechanic tested it.
My injectors could have gotten clogged, I do plan to check them out when I hook them back up, of course I'll be beyond cautious, I'll not connect the wiring to the ICM, and I'll make sure no fuel can spray anywhere on the engine.

Could the oil leak I had from my LIM gasket have messed up a ground or something?
Or is it possible even though I have the right psi at the schrader valve, I still may have a faulty FPR?
 
#19 ·
While you've got things apart, why don't you take your injectors to a shop that will flush them? That way you will know your injectors will be clean and working properly.
 
#20 ·
Very good idea enslow, thanks for the response & help.

I'd actually considered getting them flow tested and cleaned, there are two places I found on the NET, I'm not sure if there are any laces near where I live that can clean them.
Here are the places I'm considering.

Fuel Injector Cleaning and Testing

or

Injector Cleaning & Flow Testing Services

There is a good chance my FPR, or the injectors got clogged, so I'll get those cleaned as soon as I get the money, wasting so much money on a mechanic that I thought knew what he was doing has left me short on funds, so my repair will have to be put on hold till I can get some extra money.
 
#23 ·
I, too, wondered about those numbers, but I don't know what average compression values should be on a 3800. On my 4.6L Grand Marquis they should be 150-180.
This is where the wet compression test might be useful. If the compression goes way up to normal, that would suggest rings. However, if you have access to an air compressor, you might be able to put air in on the compression stroke. Then listen for air leaking out of the following places:
1) oil fill cap (remove to check): bad rings
2) air intake (remove air induction tube): bad intake valves (valves or bent rods?)
3) exhaust: bad exhaust valves (valves or bent rods?)

I will admit I've never done this before, but this is the test I've heard about in the past. It might help you decide whether to keep the engine or not. I'd probably look for a replacement engine if it needs rings. If it's valves, I don't think it's a bad job to pull the heads and check rods, and stuff. But, it is starting to look like you need to consider a replacement car. If you got a replacement in the same year but with a good engine, you'd have a parts car.
 
#24 ·
Your heads are ok, its your piston connecting rods that are bent. I would recommend R&R of the engine. If you have full coverage on your car they will cover it if only if you drove it thru a puddle and got water in the engine. We just had a costumers car in the shop with the same issue and same engine. Her ins company payed for the R&R.
 
#27 ·
Phew, that is good to hear, because I just seen it would be like 800.00 for two re-manufactured heads, on top of what I already need to spend to get it back together, that would make it take a LOT longer.
I guess the fluid that got in from the IM EGR port failure somehow caused them to be ruined?

Could I replace the piston connecting rods myself fairly easily since I already have both valve covers off?

What to typical R&R's cost for these engines?



Enslow, I thought the wet compression test, and the leak-down test were a bit different?
I am still learning of course..

I found a cheap compressor on harbor freight tools, and may end up getting it and doing the wet compression and leak-down test, if of course at this point it is worth it...
 
#25 ·
On the other hand, if you can figure out how to get it running on lousy compression so you can drive it long enough to upgrade. But I don't even know how or if it'd run on that compression. Sounds like Corey might know.

I'd be tempted to do a quick and dirty test of the injectors. Remove them from intake and place a towel underneath. Disconnect the electrical connectors to the coils to prevent any spark. Have some one crank the engine and see if you have fuel coming out. If you have fuel coming out, I wouldn't bother having the injectors cleaned at this point, given your compression numbers.
 
#28 ·
I'll test the injectors as you mentioned first, I know I can safely do so...
It is kind of pointless to have them professionally cleaned if the engine is dead.


At this point before you spend anymore money on what may be a dead engine i would have a shop check it out.
That is what I'd like to do, only I really cannot afford to get a reputable GM mechanic to check it out for me, I took it to a place that was not too far from me, well I had it towed rather, I did not really get to go meet the mechanic and see if he seemed to have common sense or not, if I had I'd have not taken it to him, because I spent around 450.00 for a new fuel pump, and a CKP replaced.
And still had a dead car that I had to wait to pay to have towed home, as I ran out of money.
I then replaced the PCM because the mechanic told me the injectors were not pulsing, I went ahead and also replaced the MAP sensor, and the TPS, and fuel filter, alone with the plugs, so I have drained what cash for repairs that I had.

If there's anything else that can be done, that is not much harder than removing the UIM & LIM as I've done, then I'd be up for getting the needed tools and trying to tackle the job myself, otherwise I'm sure I really won't be able to afford it.
 
#29 ·
ummm I would say no on doing it yourself. Please don't take this the wrong way I mean NO disrespect, I think you are know in way over your head.

"Could I replace the piston connecting rods myself fairly easily since I already have both valve covers off?"

Your piston rods are on the bottom end of the engine and already having your valve covers off will NOT help you change the rods. The easy part will be pulling the engine.

Google piston connecting rods and you will have a better understanding.
 
#30 ·
No disrespect taken, you are most likely right, I am able to do quite a bit, bit I do not have all the tools needed, nor do I have a lift if necessary.

"The easy part will be pulling the engine."
Yup, I am in over my head, I googled piston connecting rods, and found a video, there is no way I can get to those myself.

I'll check my fuel injectors, and will do a wet compression test soon, to see if its the valves or rings.
This is what a friend suggested do.

Eventually I'll get a leak-down test done, and then depending on my findings I'll probably junk it, as its starting to look like I just may need to cut my losses and save for another car somehow.
 
#31 ·
Find a good drive-ability shop in your area and have it towed in. Don't tell the you have tried to fix it yourself. Just tell them it cranks but wont fire and they will take it from there.
 
#32 · (Edited)
It would fire for just a second or two, then it would cut off like it's not getting any more fuel.

The only place I know of that may be reputable enough is the Buick Dealership, and they are out of my price range for now, I still have to come up with a few hundred to get it back together, or it will be obvious to them them I tried to work on it.
I would have to tell them I tried to work on it, unless I would want them to charge me to test things I've already tested, I cannot afford to pay somebody to do something I've already done, for instance the key has no chip, because I bypassed it with a proper ohm resistor, because a mechanic on JustAnswers told me that .580 was not the right reading at my driver side kick-plate wiring harness, nor at the theft deterrent module, come to find out that .100 ohm drop was normal, I wish I had known that before I ruined the chip trying to remove it to see if I could use it to bypass the system till i got the .680 resistors in...

I just really do not know what I should do because I really do not have the money it's starting to sound like this is going to cost, I was already looking at it taking me 4-6 months to get all the money to get the manifold back together, and replace the wire that broke as I took the plugs out, they were due to be replaced...

I don't really understand how a car that only had one prior owner, whom was an elderly couple that bought it brand new, and took very good care of it, I got it at 33k, and have always performed proper maintenance, up till I got past 100k, and found out the IM gaskets fail due to poor design, the O2 sensors is the only thing I really should have had to replace around 100k, that I hadn't already replaced prior.
I've never driven the car rough ever, so it should be in better condition than it seems, unless this is all due to the dex cool degrading the EGR port, and coolant getting into my oil, and that ruining something, other than that I do not understand how a car with such a reputable engine can break down, and have bent rods, when stuff like that happens don't you hear something?
Like rattling somewhere, or maybe you'd feel some knocking in the engine?
Because like I said before, it drove great on and off, like it was having issues getting fuel at times, then after a cylinder 3 misfire code (which I am told is my only good cylinder) the engine quietly died, as if it was either starved of fuel, or air.

When the car ran it occasionally would have a little stuttering when I'd hit the second gear, but that was on and off, and when it did run right it had plenty of power always, so I am a little confused how all of a sudden an engine can have so many cylinders go bad so fast, unless the IM problem caused this somehow.
 
#33 ·
Did a wet compression test on 1, 3, and 5 just now, since my batt is dead, and my jump box needs a recharge, the back three will have to wait, also I still do not have the 1/4" pvc I need to put on my oil can so I can get the back three a few squirts of my mobile 1 synthetic 10w 30.

1)120 Wet vs 105 Dry

3)155 Wet vs 117 Dry

5)125 Wet vs 97-100 Dry

Going to also post this in the section where I was getting help thinking it was my FPR.

Looks like 3 is my only good cylinder, it's not 100% though, as it looks like 155 would be close to 100%
Would all but one cylinder bad mean that the connecting rod did bend?
If not it looks like I have bad valves, and rings on all but 1 cylinder, and that good cylinder seems to have had the rings damaged a bit, if I am understanding what these tests are telling me.
I have a feeling when I do a wet compression test on the back three I'll see no higher then 125.


So if I get the right tools a leak-down test would be the next thing to do?
Or given my findings is my engine too messed up to be worth repairing?
 
#34 ·
You need to be aware that the wet test will always increase compression. Now that you have the numbers for the wet test, some one around here will probably be able to tell you if that increase is normal with good rings.

I would say that because the compresion didn't go all the way up to normal with the wet test, the loss of compression is at least due to something other than rings. I couldn't tell you at this point if its worth it for you to pull the heads and do valves and rods or not.
 
#35 ·
Yea, I knew the test results could go up since the oil helps bad rings seal enough to increase readings on them.

I'm starting to accept what I did not want to accept before, it seems my engine has compressed its last stroke.

I appreciate all of you trying to help me, thanks to you guys I did not spend another couple of hundred and replace the UIM & LIM...
 
#36 ·
I was told by a friend that I should have watched the compression gauge when cranking the engine, and that I should have watched for compression to stop increasing, if this is so then my numbers could be wrong.

I was also told that the timing chain could slip a tooth, and that could actually cause low compression.
I did hear a noise coming from that area a few times, when the car started for a second & then shut off.
I don't think I could check on that myself though...
 
#37 ·
your chain didnt slip a tooth. pull your plugs out. pull your fuel pump relay to eliminate fuel. unhook your icm to eliminate spark. hook your compression tester up correctly and have someone crank the engine for you. Crank it for a few seconds and watch what it goes too/ record numbers. When i did a compression check on my L36 my psi was like 185 psi to 210 psi i believe. But if you got water in you're engine and you were driving for sometime with it. You're bottom end is most likely toast. It doesnt take much with these engine to spin a bearing, usually caused from water/coolant.
 
#38 ·
I pulled all plugs, the fuel-pump relay, and disconnected the ICM when I did the test, I just did not have somebody crank it so I could watch to see when it got as high as it was going to go, I just hooked it to each plug port & cranked the engine around 5-6 times, then I went quickly and read the gauge.

I still do not know for sure whether or not water got in places it shouldn't, I posted links to a lot of pics, but never really had anybody tell me yes it looks like water/coolant got into your oil, I really just assumed that was what happened.
I seen a video of somebody who did get their engine hydra-locked, and the LIM had coolant/oil looking mix all inside of it, mine did not really look like that, I just had a little fluid in the corners of the LIM "hidden bolts", that fluid mostly looked like oil.

As bad as my LIM gasket was I'm sure fluid could have gotten sucked into the intake chambers though, because the gasket pretty much fell apart in my hands when I removed it.

I do accept what you are telling me as what has most likely happened, I just do not know what to do next.
I've so many extra parts for this car, and I know it better than any other car I've owned before, and I love the was it rides smooth, and was reliable for 133k before breaking down/dying, I'm sure it would have lasted a lot longer had I known to replace that UIM & LIM gasket, as well as the EGR stove pipe...

I cannot find any engines nearby my area, but I will keep trying to see what I can find, I'm not totally sure swapping out the engine is what I'll end up getting done, it all depends on whether or not I can find a way to earn the money to get the engine, and pay to have it installed, I could do a lot of the installation of some of the things that need to come off the current one, and go back on another one, so hopefully I can find some backyard mechanic that will let me help him do the job.

The one thing that concerns me about getting a used engine, if I was to get one I'm sure it would have to have a IM gasket job done on it, so it would not end up like my current one.

Does anybody know about how much it costs on average to get a L36 swapped?

If it is too much, along with the price of an engine, and price of parts to do a IM gasket job on the used engine, then I just may be forced to save up and try to get something used that runs decently...

I hate feeling like so indecisive, I just love my car, and hate to see it get junked just yet, I planned to get at least 300K out of it, if the body can hold up for 150k additional miles then I may try my best to get an engine swapped into it.
 
#39 ·
I'm thinking about draining my oil and opening up my oil pan to see what I can find up in there, if the engine is damaged as you guys are telling me then I should find steel, and possible bits of brass all up in there, correct?
 
#40 ·
I think that's doing too much. Your compression test numbers and maybe a leakdown test at the most will be enough to tell you what you should do.
 
#41 ·
the oil should have already been drained to check for any damage. So go ahead and do that. And get someone to crank that engine for you and lets check the correct compression on each cylinder. You cant half ass this ****, so lets do it man. Get the correct readings and we'll go from there. It takes alot of work to pull the oil pan off, but if you want go for it, i wouldnt just yet. These engines are not hard to pull, so if you have to buy a new engine, just go get a cheap cherry picker and pull this old engine. Its not that hard to be honest, just takes time and energy. Post more questions and I will try to answer as best as i can, but Im hoping more experienced people step in and really guide you correctly.
 
#45 ·
I wish man, of course I'd help in any way I could, I am not afraid of getting my hands dirty, bruised, and cut up, lol
I guess I can look at it like this, doing it myself would provide me with quite a learning experience, I've always loved to take things apart, and put them back together, I've been doing so with a lot of different things since I was 9 years old, my great-grandfather raised me, and had me in the basement teaching me how to use lots of tools at an early age, so if I try hard enough I'm sure I could pull it off.


Get the cheapest cherry picker you can get. Harbor freight has cheap ass ones and would be good for a person like you who wont do many engine pulls. no sense in wasting money. Car-parts.com will help you find a new engine in your area if you do need one. Fly me out there and we'll swap it in and be done with this!
I'm not sure why I did not think to check harbor freight, great advice, thank you.

I already scouted out a few engines at car-parts.com, that is a great site, and I've used it for a while, I'm not sure why I did not think to look there for engines sooner, there are some from as cheap as 400.00 on there, I don't want to go with one that has higher miles than my current engine though.

And I still cannot let myself forget that if I do get the engine swapped, I will still need to try to get the money together so I can do a UIM & LIM gasket job on it, as I would not want it to die prematurely.
 
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