[Moorman]

I've been seeing symptoms of this for a few months, but it's never been more than a minor annoyance. There has been a definite progression to it, in frequency and severity. It began with a rare rough idle only after starting, that wouldn't go away by sitting neutral and revving the throttle, but never affected driving and disappeared quickly. A new symptom cropped up the day before the MAF conversion, where it would take a few extra cranks to start (about the same as you'd expect after relieving fuel pressure to change the fuel filter), but would then run fine.

Now, it seems to start fine, but w/o touching the gas it idles rough and slowly dies. If I start and ease on the gas it will rev very smoothly up near 3000rpm and just die. No fits about dying, but just revs back down like completely fuel starved w/o a hint of further combustion. The harder I get on the gas, the quicker it dies. If I ease on the gas, it's a very consistent 2 seconds until it dies. There's never a trace of gasoline smell, so I don't believe it's flooding...plus it doesn't hesitate to start at all

I've pulled a plug wire and verified I'm getting spark throughout the whole process, and after combustion stops while revving down.

I've scoured for vacuum/intake leaks and found none. The O2 and fuel filter are 2 months old. I'm getting codes 21, 23, and 32...but I think those may be related to the MAF and this problem did exist before the MAF. The only code I remember pre-MAF was 21, the intake air temp.

The current phase began last night just after driving. The car was still warm and had only sat for maybe 20 minutes before I tried to start it again. I expected it to go like it's done before, and I'll drive out if it...but no such luck. I expected it to start this morning, as it's never given me problems when cold, but the only difference is that since it's cold, it tries to idle high, and we eliminate the rough idle before dying. It just revs itself up to 2krpm, and 2 seconds later dies cleanly.

I pulled the TPS connector, with no change. I've pulled the O2 connector with no change.

I'm running out of ideas so I need some from better minds than my own.....help!

 

[GreyFalcon]

Have you looked at the EGR. That's one of the first things I changed when I got this car, so I'm not real familiar with the symptoms on the MKII. It sounds similar to what happened to my '80 Celeca when that EGR started going bad. It would run fine at times and then it would just run rough and die at idle at other times. It didn't seem to affect driving as long as I had some throttle.

 

[Supra Bob]

Jason,

Have you verified that you are getting fuel? My Dad had a caddilac that the fuel pump was dying, and would do something similar... Also, check out the fuel filter and double check at the rail to make sure you are getting fuel pressure. Sounds fuel delivery related to me...

 

[Don L.]

When my fuel pump went, it gave a few warning signals, maybe for about 2 days, then just stopped. Started ok, ran for short time, die, then after sitting 10 mins, started up, ran a bit, died again. Check to see if you are getting good fuel flow should be fairly easy. I think the repair manual describes fuel check connectors. I would try disconnecting a fuel line, turn on ignition and see if you get copious amounts of fuel shooting out.

Another thought, since your idle speed gets up to 2k for a while after starting, is the ISC valve, near the throttle body. Pretty expensive device, supposedly makes a clicking noise when you initially shut down the motor. I "think" mine does this. This thing controls idle and other stuff.

Don L.

 

[SilverMk2]

21 is oxygen sensor, at least that is what it is in my 85 TSRM. If that is the case the car should run fine with a FUBAR O2 sensor, but get lousy gas mileage (i.e. run rich). 23 and 32 are the air intake temp and AFM. Both of them together you might want to investigate your AFM wiring.

Sound to me more like your fuel pump is dying. I'd get the fuel pressure tested if I were you. They tend to be a little flakey before giving out completly. Your code 21 could agree with this since it can also mean lean O2 readings.

 

[Supra Bob]

Being as he no longer has the stock AFM or AIT and has them replaced with the MAF kit.. I would say that the reason those codes are there is because they aren;t there! :wink:

 

[Moorman]

I've traced the problem to the AFM Fuel Pump Switch. I can short the fuel pump check connector and the car runs fine....pull the jump and the car dies. Split Second has tapped that wire at the old AFM harness, but I haven't gone behind the glovebox to see where the other end goes.

I need to give 'em a call anyways, since I forgot to retrieve my TSRM and elec wiring books. :?

 

[Supra Bob]

Hmm... thats interesting... I kinda wondered how they got around that. LMK what ya find out please...

 

[Moorman]

Apparently when you download the settings, it just pulls the maps. So when I created a new customer as my 'test' it went to default according to Marc. There's a place in 'Options' to set RPM at which the fuel pump is turned on. I'll let you guys know as soon as I get home and test.

 

[Moorman]

solved!

Car runs again. The setting that made the difference was under Options->System-> set to 'Programmable Signal Controller' and then Options->Output->Output B set to RPM only, and set the "Over RPM" to 200.


Would've been nice to know these details from the beginning huh? I assumed ALL of the parameters would get downloaded from the ECU, but I was wrong. Nothing quite like the beginning of a learning curve....

 

[Supra Bob]

LOL

Yeah, the learning curve can be a bitch sometimes... Glad to hear everything is worked out ok now

 

[quick]

Outstanding!

Now -- when can we get dyno results?

 

[Moorman]

Saturday. 8)

 

[century sam]

Hi !

I just saw your post and the following replies on the celicasupra forum. I got a 84 mkII, L type, and i'm presently having the same troubles that you had. The engine seems to start well, as long as i don't touch the gas, it's ok. As soon as i hit the pedal, even slightly, the engine rpm drops to about 300. Then it stays around there, until it stalls. I heard some strange noises when near stalling, like the AFM door closing or somethin...I checked for leaks, changed some vacuum hoses, it was still there. The problem is, when i came back the next day, it started as a charm ! I took it for a test drive, but after 2-3 minutes, it began to do the same, so i quickly went back. I saw that you resolved your problem, but i'm not sure to understand the way you did it. downloading for the computer and stuff... suppose i need to go to toyota or something... I just wanted to get some more explanations, since i only got the car since one month, i'm not really an expert in that technical stuff. I owned a 85 celica for 4 years, i resolved a couple of problems, but this one is really giving me some bad headaches. Thanks for the help.

 

[Supra Bob]

Sam,

Jason has an aftermarket fuel computer that he is testing for some of us who are in on a group buy on... what his problem was was related to that...

As for your problem, it sounds like a dying fuel pump to me... 84's have an intank pump, so while its a bit of work to get to, all in all its not that bad to do..

 

[century sam]

thanks for the info

thanks for the info.
I thought that it could be the fuel pump, but i wondered if the car would have started at all. If it's the normal habit for the mkII's fuel pump to die slowly from a long-suffered pain P), guess i'll have to change it. I just thought that this could be electrical, because on my other cars, when the pump died, it did it right on the spot, no waiting, no signal. So i guess i'll put a new one. If you have any more ideas, they're really welcome

Thanks