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Could my problem be a bad fuel press. regulator?

Its a 1988 Camry wagon, std 4-cyl engine (3S-FE). The engine runs fine as long as the cars sits parked, You can rev it up, it doesn't choke. Acceleration is OK at first. However, after being driven for about ten minutes slowly on residential streets, the engine loses power. You give it gas, and it just stumbles and chokes. There is an occasional sound like a muffled back- fire within the intake. The spark is remaining strong on each plug, although I can't say that the timing isn't going off....have no way to check that. The engine temp is staying normal. THe engine does have an oil leak, dripping off of the RH CV joint, so I guess the oil pump or front seal is leaking. I got a fuel pressure gauge, and installed a brass manifold (schrader) tee into the flex fuel line a couple of inches from the fuel filter (its AFTER the filter, before the fuel regulator and rail). There is

38 PSI at idle, and it goes to about 41 when you rev the engine. Thats with the car parked. When you drive it until the engine is stumbling/ lost power, there is only about 12 PSI...when I finally manage to get back to the driveway to check it. I suppose its got to be either the fuel regulator or the fuel pump, as I replaced the filter, and that did not fix problem.

My question is: if the fuel regulator was malfunctioning, could that only make the pressure....where I am reading it.... high? Also what are the specs for normal pressure... max & min?

I have the fuel tank removed and fuel pump removed from tank now, but there is no way to definitively check it, since it appears to only flake out after a period of time under load...when driving. If I just stick it into a jug of gas and run it, I don't imagine I would see anything wrong. THe screen looks like it is about 50% blocked with brown crud....but I would think that if it was too plugged up, the engine would fail to accelerate from the very start. But come to think of it, wouldn't a bad pump also cause failure to accelerate normally from the start, also?

I thought I had found a problem....there was a fuel line disconnected at the rear of the tank, but it was just the fuel vent...it was sure staying vented with the hose disconnected from it!

Funds are really tight, and since the cheapest price for a new pump I can find (an internet source) is $140, I really need to be sure it's the fix.

WHatever the problem is, its not ever setting a fault code....I guess the system has no way to detect a fuel delivery/pressure problem.

Ideas?

Reply to
geronimo
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sounds like your fuel pump to me. Can't be the regulator if you tee'ed off before that between it and your filter. Not likely the filter would drop the PSI after warmup like that. It would be a constant drop. Fuel pump is failing after getting warmed up. Maybe go find a used one in a junk yard to save some cash.

cheers

davemc

Reply to
davemac

sounds like your fuel pump to me. Can't be the regulator if you tee'ed off before that between it and your filter. Not likely the filter would drop the PSI after warmup like that. It would be a constant drop. Fuel pump is failing after getting warmed up. Maybe go find a used one in a junk yard to save some cash.

cheers

davemc

Reply to
davemac

This is classic Camry Coil issues, try cleaning or replace it, the issue is so common its ridiculous. Moisture doesnt cook off till its gets hot then it shorts out.

Reply to
m Ransley

uhm, not when he's measuring fuel pressure of 12PSI from the filter. Got to be the pump.

Dave Mc

Reply to
davemac

Yea, I still have a strong spark on each plug wire. I head about that coil problem, so I took the distributor coil assy. apart and checked it, but there wasn't a trace of moisture (or oil) inside it. Just have to bite the bullet and get a new fuel pump, I guess, because its too much a roll-of-the-dice as to whether I get a good one or not from the junkyard. Could fail the day after I put it in, and they would not warranty it at all. Just wanted some confirmation that it couldn't be the fuel press. regulator. Thanks, Geronimo

Reply to
geronimo

According to the Haynes for my '97 Camry, the fuel pressure should be 44-50 PSI and hold pressure should be 21 PSI after 5 min. Don't know how many years forward are the same as yours, might be quite a few so you might be able to get a late model pump. If so, many salvage yards will with a guarentee, usually at appx 10% more here. HTH, Dave

Reply to
davidj92

David, do you know if it is suppose to maintain that pressure range under any load/throttle setting?

Also, I found that some>ger>> Yea, I still have a strong spark on each plug wire. I head about that

Reply to
geronimo

The pressure should stay at least somewhere close to the 44 PSI when running. If it doesn't then the injectors probably won't work correctly and you'd get a lean burn, which is probably what is causing the detonation you're hearing in the intake. When you shut the key off then the pressure should be at least 21 PSI after 5 min. Does the pump make any loud or unusual noises after it gets warm? It should not change noise patterns from cold to warm, if so this is an indicator of a pump failing. Also, the injectors or a hose could be leaking causing a drop in pressure. When it starts to run bad, shut it off right away and pull a plug. If it's wet and no ignition problem then you're getting too much fuel which would indicate a pressure regulator or injector(s). If plugs are dry then it's probably the regulator and/or pump. I don't think the vent will cause a run problem on yours as it is probably vented to atmosphere. On OBDII the vent goes to a charcoal canister and if it were off then there could be a vacuum loss when the purge valve cycles.

Reply to
davidj92

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