2.3 issues...extensive work/tests done already please help.

[schlutzer]

Okay so first of all I'm going to list all the parts that are new but were not replaced trying to fix this problem:

plugs/wires
cap/rotor
fuel filter
in-tank fuel pump/sending unit
air filter
all vacuum hoses
timing belt

Now for the problem; I have been experiencing two likely related problems. first off after i drive the truck and get out i notice a strong fuel smell coming from under the truck all the lines are good and so is the tank, I checked when replacing the pump.

I get flat spots and slight surging while driving as well as periods of power loss in varying degrees most noticeably in the morning. overall the truck feels slightly less peppy than it used to. it idles up and down ~200rpm ( will clean the IAC tomorrow I can hear it hissing; is that bad?)

I've done a compression check got exactly 160 psi on every cylinder (not bad for a 21 year old motor!)

Fuel pressure check was a little odd, I think. It took about 10 seconds of idle to come up to 30 psi. When revved it would go to about 35 then back to 30. if held at say 2500 rpm it would go up to about 35 again then back to 30. If i pull the vacuum hose off the regulator it shoots up to 40 psi and just stays there no matter what I do. Also the hose smells of fuel.

Timing is set to about 13 degrees BTC because it runs better at this setting, at 10 degrees it was nearly unbearable.

Okay gods, there you have it. BTW my truck is an 88 xlt 2.3 5spd 2wd ext cab

Sorry for the long post! but i really want to be able to say "I fixed it!" and not pay a mechanic...

 

[Mark_88]

Well, I'm no Guru with the FI engines, but a recent post by another member learned that he had a hole in the top of his cat and this was probably a source for smelling fuel after startup...when the cat is hot it should help burn off excess fuel and if your vac/EGR system is working well your EGR should also suck excess gas back through to be burned off...

So...check your exhaust for leaks and try a vac test...you can also test the EGR diapham if you have a tester...if that is leaking it will cause excess fuel to be left in the exhaust since it is not being drawn back through to be burned...

Also check the top side of your cat for leaks...this may require pulling off the heat shield...but if you start up your engine...while the tail pipe is cold...put your hand over it with the engine running and hold it there for a few seconds making sure you seal the pipe...when you pull your hand away there should be an audible "POP" sound...if not...you can suspect a leak in the exhaust system (this trick was shown to me by an E-Test tech...that's how they test for leaks)...

 

[schlutzer]

exhaust is all new and good thanks for the idea tho ill keep that info stored away incase something like this happens again ill have one more thing to check

 

[BlackDogSociety]

If it's hissing at the IAC then there is probably a leak. This is the same as having a vacuum leak which would explain your symptoms. I'd replace the IAC...

 

[BlackBII]

Okay so first of all I'm going to list all the parts that are new but were not replaced trying to fix this problem:

plugs/wires
cap/rotor
fuel filter
in-tank fuel pump/sending unit
air filter
all vacuum hoses
timing belt

Now for the problem; I have been experiencing two likely related problems. first off after i drive the truck and get out i notice a strong fuel smell coming from under the truck all the lines are good and so is the tank, I checked when replacing the pump.

I get flat spots and slight surging while driving as well as periods of power loss in varying degrees most noticeably in the morning. overall the truck feels slightly less peppy than it used to. it idles up and down ~200rpm ( will clean the IAC tomorrow I can hear it hissing; is that bad?)

I've done a compression check got exactly 160 psi on every cylinder (not bad for a 21 year old motor!)

Fuel pressure check was a little odd, I think. It took about 10 seconds of idle to come up to 30 psi. When revved it would go to about 35 then back to 30. if held at say 2500 rpm it would go up to about 35 again then back to 30. If i pull the vacuum hose off the regulator it shoots up to 40 psi and just stays there no matter what I do. Also the hose smells of fuel.

Timing is set to about 13 degrees BTC because it runs better at this setting, at 10 degrees it was nearly unbearable.

Okay gods, there you have it. BTW my truck is an 88 xlt 2.3 5spd 2wd ext cab

Sorry for the long post! but i really want to be able to say "I fixed it!" and not pay a mechanic...

The diaphragm in the FPR could be leaking, and is somewhat common.

With the truck running, pull off the vaccum line on the FPR and hold it right next to the port on the FPR, can you see any fuel/fumes getting 'sucked' out?

 

[CheapRanger]

If it's hissing at the IAC then there is probably a leak. This is the same as having a vacuum leak which would explain your symptoms. I'd replace the IAC...

Is there an actual test for the IAC? I had an issue with it before and replaced it. I have already had to pull and clean this once (about a year ago) and believe I need to do so again.

 

[scotts90ranger]

if you pull off the connector for it and the idle drops it works, other than that I don't know of anything

 

[olranger]

well if it happens mostly in the morning while the engine is cool, what about a temp sensor. if it is messed up and not reading right it wont give it fuel like it should cause it wont know what temp the engine is. try that, hard to say without the truck in front of me.

 

[schlutzer]

it happens worse in the morning... but not more often. the same frequency of instances but when its cold they are more severe.

I'm leaning heavily toward a bad FPR as my TPS tests just fine. and should it really take 10 seconds to build fuel pressure?