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Unhappy Please Help Frustrated

Sorry for the long post but please HELP..... Anyone
I have read almost all the posts on no start and starting problems and cant find my problem yet. I need your help. By the way this is a good forum. my 87 944t wont start. I have fuel pressure at 39 PSI, spark at plugs, tested the injector wire with a noid, they work, and can pull start the car and it runs good above 2500rpm no miss, no backfire, with heavy acceleration can even spin tires in 2nd gear. but once the rpm's drop lower than 2500 or so, the car dies and will not start. I have used some starting fluid before the intercooler and again at the throttle body, will not start. I have used a voltmeter on the TPS and it reads 1 to 3 ohms at closed with a wire on terminal 2 of DME and ground. and the ohms go up to 2.4 and higher at WOT, (that is not good but that wouldn't keep the car from starting), and with a wire form 22 and 23 on the KLR the readings are perfect I have positioned the TPS so that at 1degree the clicking sound is heard and have cleaned the TPS with contact cleaner. if there is something someone could suggest to me, I would greatly appreciate it very much. my hair is very short from all the pulling I've done on it...
signed hopelessly confused

Old 10-08-2004, 09:02 AM
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plugged air filter? out of adjustment AFM?
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Old 10-08-2004, 09:10 AM
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at 3000RPM's the car runs great, I have sprayed some starting fluid on the intake at the same RPM's, with no changes. The spark is good at cranking, and is constant. If it was not constant, I'm not sure if it would run at any speed. On a vacuum leak, could that cause a no start condition. Also I have the Huntley racing mass air flow with the split second ARC2, ARM1 and EGO1. sorry, I should have posted that earlier.
Could the idle actuator create a no start condition. if so, how can I test the idle actuator I have again pulled the car in first gear and it starts great at 20 MPH, drive it around and had a friend spray the starting fluid then while I am holding the Accelerator peddle, and the car runs great. I Pulled off the intake and the vacuum hoses from the idle actuator are loose but not off and the timing valve hoses are loose, ( I'm able to turn them with ease on their connections). could this cause a no start. I am very grateful for the responses to this post. Thank You
Johnnybegood
Old 10-08-2004, 04:11 PM
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Yea but you need to remember that The fuel pressure at idle may be higer due to the HR MAF kit. WHen I installed mine in my NA I was told by HR to adjust the fuel pressure to like 45psi or somthing.

Jonny, When was the last time you calibrated the ARC2???

How are your speed and reference sensors???

Have you checked the idle controle valve???

Have you checked all VACCUM lines, if there is a leak it could case it to stall.
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Old 10-08-2004, 07:58 PM
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I have changed the clutch to a spec stage 3 hybrid and the head gasket to a cometic head gasket. The speed and reference sensors are new and are tight and set at .8MM from flywheel,( shredded the first two in the bellhousing after the first install, and had to take everything apart again, then after the finished job, a friend dropped a nut in the flywheel timing window at the top of the bellhousing so back apart again). so this is a new problem. after the clutch and head job, I drove the car home, At a stop sigh It began surging from 700RPM's to 1200RPM's, then I Accelerated and it drove fine. At the next stop sigh, I let it go to idle the surge started right away ad then died. No start after that. (its been on blocks for a little over a year; not much time on my part). (Drove it home at 9:30 Saturday night; I cant use boost for 500 miles because of the clutch; and I didn't cut off anybody on the road, but at 12:30 Sunday morning someone shot a pellet through me drivers window at point blank range... ouch). The timing is right on, I've checked it several times. and its a springed idler that keeps the cam belt tight, all belts are new and fuel is new. the fuel pressure reg is a Huntley racing. Also if the coil is weak, could the car run good at higher RPM's. I would think that a weak coil at higher RMP's would either backfire or some other sigh of weakness, I'm not sure. The idle controle valve(idle actuator) has been removed and I am cleaning it with carb cleaner. I dont know how to calibrate the arc2. if you mean to adjust the the units 4 knobs, yes I have. Is there is another way to calibrate the unit?. I dont know how. If you could tell me, I would be indebted to you
Thank you guys for all your help on this
Again thanks Johnnybegoodrn
Old 10-09-2004, 01:16 PM
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No there is no other way to clibrate the arc2 just the 4 nobs. Sounds like you got one hell of a 951, got any pics??? How is the coolany level in your CAR???? Have you check all vaccum lines????
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Old 10-09-2004, 03:57 PM
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Here are some pics of the engine and console before the clutch and head job
Old 10-09-2004, 06:53 PM
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hey FR - a turbo is supposed to have like 38psi of pressure...
2.5 bar = about 37psi
has a 2.5 bar fpr
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Old 10-09-2004, 07:29 PM
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Umm, my fpr shows 2.5 bar rather clearly.
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Old 10-10-2004, 02:29 PM
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I think they are all supposed to have 2.5, I am pretty sure my n/a has a 2.5 bar regulator as well.
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Old 10-10-2004, 02:35 PM
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With Huntley racing they suggest 42 to 45 psi with their fuel pressure reg
Old 10-10-2004, 08:31 PM
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@idle
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Old 10-11-2004, 01:59 PM
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ok I'll try that. I have replaced all the clamps and cleaned the idle actuator with carb cleaner checked all the hoses on top of the engine. I think that I will plug the small hoses going to the firewall and all the small hoses that I don't need to start the car. if there is a vacuum leak in one of these lines then the car should start if this doesn't work then I am lost. Tomorrow, I will go through all of the same things again. Spark, fire at injectors fuel pressure, timing, ohms at the tps. If all this is good, I don't know what else to do. Should there be some kind of reading, when cranking on the engine, on a vacuum pressure gauge. I have a gauge that reads vac and boost. When I crank on the engine the needle may move about 1 to 1.5 marks not very strong. After about 10 to 12 cranks on the engine, it acts like its out of time for one revolution and goes back to cranking fine. This varies and is not a constant number 10 to 12. some times its only 8 to 10 cranks. To me that sounds like a vac leak but not sure. The timing is right on, I've checked it and had a friend check it after the car has run ( pull started), and after cranking the engine.
Thanks for all, everyone has done to help me. If no one helps anymore I understand. sometimes its time to let it sit for a few months. I don't want to do that but, am left with no choice
Thanks again for all your help
Johnnybegood
Old 10-11-2004, 05:33 PM
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these guys are not going to leave you hanging...

Johnnybegood are you really an RN ?
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Old 10-11-2004, 07:46 PM
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I feel your pain. 1984......

No start all of a sudden a few months back. Spark? Yup. Fuel pressure? Nada. Time to check thigs out. Original DME relay..Check. Might as well replace. Power to fuel pump at cranking? Yup. AHA!! Fuel pump not pumping!! Long clip lead pump to battery. Nada. Replace fuel pump, filter, fuel line to tank. Car starts. Runs for one day. No start again. Currently scratching head. Pressure regulator? Damper?

When they run, they run well. Whan they don't, they are hell to diagnose.....

Imagine giving one to a 1950s style mechanic..........Yikes!!

Every year brings more and more sensors..each compounding the possibilities of failure. Anyone think the piston engine is rapidly reaching the point of no return?

one sensor...one possibility

two sensors... three possibilities (either or both)

three sensors... any one, any two, or all three (seven possibilities)

four sensors...any one, any two, any three or all four...sixteen(?)

And how many are there on the modern engine?
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Last edited by Moneyguy1; 10-11-2004 at 08:44 PM..
Old 10-11-2004, 08:35 PM
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The 951 uses a 2.5-bar FPR, part# 0280.160.227. If you buy it in the aftermarket, you'll get a black unit with 2.5 bar written right on it. The rating is with the vacuum line disconnected. Fuel pressure should be 36psi at idle. With vacuum line connected, the manifold vacuum will pull down pressure to 2.0 bar or 29-30psi. But due to different stages of wear and tear or upgrades, different cars will pull different vacuum amounts in the manifold, thus leading to different idle fuel-pressures. That's why you only want to check idle fuel-pressure with the vacuum hose disconnected. Here's the page of interest : DME/KLR TestManual - Page16.

johnnybegoodrn, which Huntley MAF do you have? Tom Mguin and I both had the MAF-4 and Turbo-2 combo and we both fought low-speed/idle issues for years. I dumped it about 5 years ago, however, we both did come up with some ways of making it work without dying. One of the problems was the MAF, being a big one for high-CFM flow measurements, wasn't very accurate at low-flow/idle conditions.

Hook up a digital voltmeter to the MAF's signal going to the DME. So tap into the air-flow signal wire DME pin#7 (green/red-stripe wire) after the ARC2 and before the DME. Watch what the signal is at various operating conditions. On both our kits, Tom & I noticed that sporadically, the MAF-output drops to 0 volts randomly at low-flow conditions. We ended up rotating the MAF-sensor itself so that the hole in the pick-up tube was on the outside of the bend on the pipes. This is where flow-velocity was highest, so we didn't get drop-outs from the MAF.

The other problem you might have, is a TPS adjustment.

"but once the rpm's drop lower than 2500 or so, the car dies and will not start."

" I have positioned the TPS so that at 1degree the clicking sound is heard"

Hmm, the close-throttle contact switch may not be correct.

First, check your throttle-plate closed position:

- remove the intercooler-pipe so that you can see the throttle-butterfly.
- Loosen the throttle-cable so that you have some slack.
- See how large the crack at the bottom of the throttle-plate. It should be less than 0.5mm or so.

One way to adjust this is to:

- unlock the throttle-plate stop-screw on the side of the throttle-body.
- turn-in screw so that there's a gap between screw and throttle-plate arm.
- turn-out the screw so that it barely contacts the plate arm.
- then turn it out 1/2 turn more, this will keep the plate barely open the proper amount.

Second, adjust the TPS closed-throttle switch:

- unlock the TPS-body by loosening both screws.
- rotate TPS so that it clicks right as the throttle is opened
- temporarily tighten down the screws.
- verify that the TPS clicks right as you open the throttle and clicks just as you're closing the throttle all the way.
- verify that pins #4 & 6 are connected (zero ohms) when the throttle is closed.
- just as you rotate open the throttle (like no more than 0.1mm), the click should be heard and pins #4 & 6 should be disconnected (infinite ohms).

Third, check the TPS-positioning signal:

- hook up digital voltmeter + probe to KLR#22 (white/green-stripe wire), use anything for ground, leave DME/KLR connected
- with car ON, but not running, check voltage with throttle-closed; should be 0.25v
- gradually increase throttle-opening, voltage should increase steadily with no spikes or drop-outs.
- full-open throttle should 3.75v or so on the TPS-position line.

I suspect our TPS is set improperly so that it clicks too soon as you let off the gas. When it clicks and connects pins #4 & 6, the DME switches to the idle fuel maps and shuts off the fuel. Only after the RPMs drop lower than 1700rpm, does the fuel get turned back on. So if you're driving along at 2500rpm and let off the gas ever so slightly and the TPS clicks, you lose all gas and the engine dies.

Last edited by DannoXYZ; 10-13-2004 at 05:24 PM..
Old 10-13-2004, 04:32 PM
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well her it goes,
I tried to go back to the original chips and afm. the problem is that I didn't mark the chips. I called some people, linsey racing is one, And was told that if the chips where in the wrong places ( dme chip in klr slot and klr in dme slot) that It should not fry the computers. no blame on anyone, my fault for not marking them. well know I don't have spark or fuel pressure. I jumped terminal 30 and 87b together and fuel but didn't jump 87 into it. will have to do that tomorrow. did I kill the dme and klr or just the dme or the relay. if you can help, I would be grateful
thanks Johnnybegood
Old 10-13-2004, 06:39 PM
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Quote:
Originally posted by johnnybegoodrn
well her it goes,
I tried to go back to the original chips and afm. the problem is that I didn't mark the chips. I called some people, linsey racing is one, And was told that if the chips where in the wrong places ( dme chip in klr slot and klr in dme slot) that It should not fry the computers. no blame on anyone, my fault for not marking them. well know I don't have spark or fuel pressure. I jumped terminal 30 and 87b together and fuel but didn't jump 87 into it. will have to do that tomorrow. did I kill the dme and klr or just the dme or the relay. if you can help, I would be grateful
thanks Johnnybegood
There should be some numbers on those chips........ what do they say.
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Old 10-13-2004, 07:09 PM
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Don't bother with the fuel-pump test. If you car runs at all, like above 3000rpm, you've got fuel. There's no RPM-sensitive switch or sensor on the fuel-pump circuit, so it's fine.



" I called some people, linsey racing is one, And was told that if the chips where in the wrong places ( dme chip in klr slot and klr in dme slot) that It should not fry the computers."

You won't hurt the computers, but one of my chip-kit customers got the chips mixed up. He ended up blowing up the DME chip that was inserted into the KLR. It blew so hard, it actually blasted a hole the size of a dime off the top of the chip and dented the housing on the KLR box...

Also the MAF is hard-wired into the harness, so you'll have quite a chore to undo it and install the AFM. Make sure you restore all of the stock lines, especially the air-temp sensor. It's wired to a fixed signal in the MAF that simulates 70-degrees all the time. Hopefully this process won't introduce other problems that may require additional troubleshooting. If you haven't already started on swapping back the AFM, I'd check the TPS first since it's so much easier.
Old 10-14-2004, 12:07 AM
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DannoXYZ thanks for the post.
the computers are good. there is fire know, how did that happen, I don't know. I think that when I unplugged the dme it reset itself.
DannoXYZ, you said that you dumped the huntley system, what system did you go to and what is good out there. I hope that a fuel management system will correct my problem. I haven't had time to check the tps #4 and #6 yet but tomorrow I will. thanks for all of the info johnnybegood

Old 10-14-2004, 03:17 PM
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