Knowledgeable Tech -Starting/Performance problem needing assistance

[tomtom72]

Nobody said anything as to what a check of the fuel pressure regulator had to say? I would have checked that after I did the pressure test, KOEO by the book. The FSM protocol insures that both pumps are okay. The pressure was a bit down so the filter was swapped. PSI still down, so pump assembly was checked & cracked hose was found. This isn't consistent with loading up, no? Would not the motor be lean & smell lean?

Not trying to be a wise guy, but if it's loading up & shutting down from too much fuel....just saying the regulator bears a look, right.

If all of the above isn't the case then it's too lean, right? Nobody said anything about a lean smell from the exhaust. That is usually consistent with OEM injector failure as it's the coils that are the weak point on the 90's? The OE injectors rarely foul up bad enough to just dump fuel? I thought the design prevented that? Or do I have that wrong? Do we know for sure that the OEM injectors are still in the car? I can see my brand of injector thru the legs on the plenum.

Just my fwiw. Maybe two separate failures are at work here? I have a hard time matching the described symptoms to what was found to be physically wrong....or I'm stuck on the loading ( too rich ) up & shutting off symptom which makes me want to check the regulator & then move on to other things.
Please don't take me the wrong way! But something don't add up.


Tom

[Paul Workman]

Originally Posted by XfireZ51

You say you are showing a lean condition and a secondary fault code? Vacuum leak somewhere? 7.5ms sounds like a LARGE PW for idle. But a lean condition may call for that and flood the motor. What do the plugs look like? R they wet? If you put a scan tool on it, just turn the ignition to ON and scan for the different nominal sensor values. Make sure each sensor is reading normal at 0 RPM ie MAP 97-100kPa depending on location, O2 .450v, CTS, MAT, etc. Check connections to ignition module. Did a critter gnaw on a wire?

Hey Dom. Good you could check in. Hey, check me out: I considered that "lean" code too, but I put that aside b/c the ECM is in "open loop" until the engine warms up. I mentioned O2s and cross-counts, but as the OP said, it is a moot point if it won't idle more than 30 seconds.

At issue too, is the lack of codes or sensor readings, but a full set about now AND seeing the plugs would be more than a little helpful, huh?

And to TomTom... yer right about the regulator. If the diaphragm is cracked...who-boy! Talk about flooding! Again...MORE & MORE I wanna see dem plugs...especially the back 2 (where the regulator hose enters the plenum)!!

(I should be out working on my own car, but this problem has me intrigued!)

P.

[lbszr]

The OP mentioned spraying raw gas in the intake, it runs better. If this can be verified, possibly by a squirt or two to keep it running. This would rule out ignition, and internal engine problems and definitly be a lean condition to deal with. Although probably not the safest method if it decides to backfire at the same time.

Has the throttle position sensor and map sensor been checked for correct inputs to the ecm?

Mine had an intermittent O2 sensor causing mine to barely have enough power to move and die occassionly with no code. After about a month of this, it finally threw a code and told me which one. So I wouldn't rule out a bad sensor somewhere because of no code.

[XfireZ51]

It also sounds like it may be starting in "Limp Home" mode. What happens if you try feathering the throttle at start-up? It may not run long enough to set a code. With KEY ON, not start, does the CEL flash once or just come on?

[Paul Workman]

Originally Posted by tomtom72

Nobody said anything as to what a check of the fuel pressure regulator had to say? I would have checked that after I did the pressure test, KOEO by the book. The FSM protocol insures that both pumps are okay. The pressure was a bit down so the filter was swapped. PSI still down, so pump assembly was checked & cracked hose was found. This isn't consistent with loading up, no? Would not the motor be lean & smell lean?

Revisiting your post (and others). Good points. But, I'm getting cornfoozing info here (could be just the way I'm interpreting it too, I suppose.)

I'd really like to see the list of "switch on" scanner codes, and then capture a set while it is running (of sorts).

In cases of "No codes", lots of fueling issues slip under the radar (it would be nice to have a FP readout on the dash or maybe the "A" pillar - I'm just sayin). But, fueling issues do not escape the plugs, and we've yet to hear/see how they look. (I'd believe plugs before what my nose would tell me at the exhaust pipe. Running with or without cats, or condition of the cats themselves makes a big difference in smell - to the point I have no confidence in MY snoot. Your snoot may be calibrated, and as such a valuable troubleshooting tool! )

Originally Posted by tomtom72

Please don't take me the wrong way! But something don't add up.


Tom

I agree. I guess we're all waiting for more info...

P.

[sjs]

Originally Posted by Paul Workman

Revisiting your post (and others). Good points. But, I'm getting cornfoozing info here (could be just the way I'm interpreting it too, I suppose.)

I'd really like to see the list of "switch on" scanner codes, and then capture a set while it is running (of sorts).

In cases of "No codes", lots of fueling issues slip under the radar (it would be nice to have a FP readout on the dash or maybe the "A" pillar - I'm just sayin). But, fueling issues do not escape the plugs, and we've yet to hear/see how they look. (I'd believe plugs before what my nose would tell me at the exhaust pipe. Running with or without cats, or condition of the cats themselves makes a big difference in smell - to the point I have no confidence in MY snoot. Your snoot may be calibrated, and as such a valuable troubleshooting tool! )




I agree. I guess we're all waiting for more info...

P.

Thanks to all who have replied, lots of great info ... thanks especially to Paul as he read all the information in my posts and went even deeper.
I apologize for not getting back sooner, but some last minute stuff came up and I had to work most of the weekend. Also the car is in my garage not at my shop building so I don't have all my tools, hoping not to have to tow it!!!
Anyway, more info as requested with what I had time to learn. Fuel pressure regulator is fine ... changes with vacuum, holds pressure and vacuum and doesn't leak fuel internally or thru the vacuum port. Plugs truly are soaking wet, thats why it starts and runs okay after sitting for a couple hours, but after 15 seconds of operation time it loads up and NO throttle position keeps it happy. Won't restart unless in clear flood mode.
So .... Paul I agree completely .. I need to put the internal engine health question to bed with a compression test ... I thought crank vacuum and idle vacuum were low (althought hard to prove with a rough running engine) ... so tommorow I am going to pull of the plenum and compression test the old girl .... while the top is off I will resistance check the injectors and coils. I have an ignition DSO scope but it won't run long enough to accurately test it ... so upon everyones advice I think I will just replace the injectors and ignition while I am there ... if the motor is solid. If it isn't car just may have come up for sale as I don't have time this summer for a tear down - love the car just don't have time to play like I used too. If I did take the time to tear it apart - then it will get a full overhaul ... I don't like to make repairs twice! I will let everyone know if the stuff on top fixed it or if it is getting the reluctant "for sale" sign. If anyone wants a small project let me know. Thanks again to everyone.