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1987-1991 Parley with regards to your 1987 to 1991 Bonneville, Olds 88 or Buick Le Sabre Please use General Chat for non-mechanical issues, and Performance and Brainstorming for improvements.

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Old 06-17-2006, 11:03 PM   #11
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You can check for power going to the ICM. Remove the wiring connector going to the ICM. With the key on there should be 12 volts at the P terminal of the wiring connector. The P terminal should be a pink or pink/black wire at one end of the connector.
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Old 06-18-2006, 01:17 AM   #12
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ICM? "Ignition Control Module"? I already know I have spark, what I'm not getting is the fuel injectors firing.

Did you mean "ECM"?
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Old 06-18-2006, 01:29 AM   #13
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Quote:
Originally Posted by bastard
Sorry to hear about the wreck. I always wondered what one of these drivetrains would be like in a VW type off road chassis.
"Corvair" has always sparked my fantasies.
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Old 06-30-2006, 11:18 AM   #14
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Been too busy to do anything with it. I'm going to hook up the Auto X-ray and see if it can talk. If not, it'* a new ECM.
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Old 07-20-2006, 01:58 AM   #15
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Okay, I haven't done a lot since last month, but I have done more than nothing. . .

I hooked up the Auto Xray, and got "vehicle not responding" when I attempted to scan. I checked for voltage at the ECM connectors, not knowing exactly what to probe or what to expect (all I have is a general Haynes manual, which doesn't tell diddly about that), verified 12 volts on the orange w/white stripe wires (or was that pink/white? can't remember for sure) and red wires (one type switched, one unswitched). So, I went to Checker and picked up a reman ECM (required my old PROM), installed, didn't start; scanned, "vehicle not responding". So, it sat until tonight.

The '90 SSE set the SES light today, scan said TPS voltage too low, taking a quick look at that I discover the connector is broken at the TPS - but the pins were still making contact. Probe for voltage, get 5 V on A, zero on B & C - again, not knowing exactly what to expect, I went out to the '91 and did the same thing - got 12, 7, and 7, respectively (with ignition on - I didn't think to check it with ignition off). Poked around the harness of the SSE where it goes under the alternator and PS pump, it wasn't routed too cleanly, unwrapped part of it and made sure nothing was pinched or cut, rewrapped it. Put the 91'* TPS on the SSE, set it to .49 VDC at idle, SES light goes away, that'* fixed (runs better than it has since installing the L27, in fact - TPS must have been weak all this time).

Thinking that I may have crushed the same harness on the '91 when I did the alternator swap, checked it, no problems. Cleaner than the SSE, actually.

One other thing I haven't mentioned yet: When cranking the '91, the fuel pump doesn't come on until oil pressure comes up. Before this problem started, you could hear the pump come on for 5-10 seconds as soon as you turned the ignition to "On".

So, any thoughts on what these latest bits of evidence may be trying to tell me? I'm real close to pulling the engine/tranny out of the '91 and putting them in the SSE - it always ran better and the transmission operated more smoothly than the SSE ever did. But, my son would like the '91 to drive if we can figure this out.
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Old 11-26-2006, 08:41 PM   #16
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For what it'* worth update:

The car has been sitting since the last post. I ordered a factory manual earlier this month, arrived last week. There certainly wasn't a direct answer there, but sufficient information existed to finally locate the problem.

The key from the manual was the lack of an SES light. That said ECM power was the problem. I traced down the circuits it said would cause that, no dice, everything was fine. So, I started checking voltages at the back of the ECM connectors with the voltmeter ground probe to chassis ground, comparing them to tables in the manual. Everything looked fine except the TPS power was near battery voltage instead of 3-5 volts. I checked it referenced to the ground wires on the ECM connector, and surprise, surprise, 5 volts. I then check continuity between the connector ground wires and chassis, found high resistance. Looking at the ground wire that goes to the battery ground cable, the insulation looked like it had gotten hot right at the neg batt terminal, so I routed it directly to the top post - still high resistance from the ECM connector to chassis. Apparently the ground wire through the firewall was blitzed. I routed a wire from the chassis ground right on the passenger kick panel spliced to the ECM grounds, a bingo!, turning the key on produced an SES light. Ran to the parts store and got a TPS to replace the one I stole for the SSE, installed it. I was doing all of this troubleshooting with the battery charger on the battery because the battery had gone dead while it was sitting, still wouldn't start. Jumped it, fired right up. Had a TPS voltage low code, chased that, went away, runs fine. Got a new battery this afternoon, it'* running like nothing happened.

Weirdest thing I've ever seen - killing a connector ground wire because of a poor ground to the battery while trying to start the engine. Wasn't hard to fix, but sure was a pain tracking it down.

So, you guys were right about the ECM ground, but the location of the ground problem wasn't quite what any of us expected.

I suppose I should run a clean wire from the ECM to the battery negative.
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