Intermittent stall hard start need help trade BEER

[theparkinggargae]

Alright, so I bought this wonderful 89 Bonnie LE. It's got about 100k miles. Runs fine for about 150 miles so needless to say I fell in love with the comfort and ride. Then I start having problems in hot weather with stalls. No overheating. Won't start after flashes cel and temp light. I don't have a scanner so I thought I'd self diagnose and replace. Since then I have replaced the crank sensor, cam sensor, ect, coil, icm, iac, thermostat, Maf and maybe some other stuff too. Since the first replacement it has been even harder to start. But I think I have replaced all correctly due to the fact that one day after all parts it started right up and drove for about 5 miles. I drove it both directions above and below 45 mph, stopped reversed with no problems. When I parked in the driveway it died and wouldn't start. Any ideas on what is wrong with this car? If anyone in the Denver metro area has a scanner I'll trade you some homebrew beer for a reading. Thanks

[Mechanical Mike]

You don't need a scanner for your 89. Read the article in the following link & let us know the code.
viewtopic.php?f=51&t=8689

[theparkinggargae]

Thanks for the link. I didn't have time to fully check last night, but this morning before work I tried to read the codes. It gave me the 1-2 blinks on the CEL like the link said but it just repeated the 1-2 for more than nine times. I may have disconnected the battery on my last part install and cleared the codes. So tonight I plan to try to run the car until the CEL lights and car stalls and then repeat the code method. The only thing else I noticed is when the CEL was flashing 1-2 in between the temp light flashed once and then 4 times. It only did that once but each time the temp light flashed I could hear a mechanical clicking noise. Have you ever heard of that? I will do more diagnostics and post findings when available.

[Jrs3800]

This seems like an ECM failure to me, But its hard to say without at least having a scan tool hooked tot he car to see what the ECM is seeing and doing..

When you try to start it does it start at all, do you loose spark ? Does the engine start for 2 or 3 seconds and then just die?

When you installed the crank sensor did you make sure it was aligned properly?

[theparkinggargae]

Alright, tonight i went to start the car and had the usual problem. It cranks and sound like it wants to fire but doesn't. When i press the gas just a little, it fires right up but only runs while gas is slightly depressed. This is not WOT but barely any. As soon as I let off it dies. It didn't set off any codes it only read 12 12 12 and kept going. I put the crank sensor in correctly, i think, I spaced it with a gap gague like it said. I didn't set motor to TDC if that matters. but sensor doesn't hit or anything. Looks like it rotates smooth, and old one didn't look bad or broken. Also car at one point after parts were installed ran smoothly for about a 5 mile ride. I have also looked over any wires i can see for grounding issues, but this car looks basically pristine. What are the indications of a bad ECM??

[Jrs3800]

So if you hold the throttle it will start and run? then if you let off the throttle it dies?

When you have the throttle slightly depressed does the car run ok?

[theparkinggargae]

Yes, if i press the gas just a little, it fires right up. When it's running it sounds good aside from the fact it will idle down till it stalls. If i let off the gas she chugs out and dies. Will not start without gas depressed. I don't have a fuel pressure gague but I have replaced fuel pump, removed pulsator?, replaced fuel filter, and as far as i can tell I have fuel at the schrader valve. I didn't adjust my IAC to the old one, but i was under the impression as long as it wasn't sticking out too far to cause damage when installed, it would adjust itself?? Side note...... The paper clip ECM reader....will this work on my 90 blazer?? plug is the same but it's TBI. Thanks.

[Jrs3800]

The car should learn to idle on its own, But it will not relearn the IAC position until the car is at full operating temp above 40 Mph for a given amount of time..

Did you use a used IAC or did you buy a new one?

[theparkinggargae]

I replaced with a new one. The new one looked identical bit the pintle was retracted more. I replaced IAC and afterward the car actually started. It reacted the same as before. It would idle fine and the die after 10-15 mins. So I would restart if it died and got it up to temp. After it was at operating temp I drove it above 40 but only for a couple blocks. It drove nice and fine until I parked it at home. It died as I pulled in the driveway. After that I couldn't get her to start. Since then it won't idle on it's own. I would be willing to drive above 40 again for longer but I don't trust she'll run long enough or won't start after she dies. The only part I can think that I haven't replaced is the TPS. Any ideas for what else to try?

[Jrs3800]

I am almost thinking ECM with all of the parts that you have replaced.. But can't promise that would be the solution as I can't be there to look at it.. If you were my neighbor we would have swapped my 91 ECM in there just to see...lol

[theparkinggargae]

I think ECM will be my next part. It looks like it's only about 80 bucks. Are there any tricks to ECM replacement?? When I ran the car last night I held the gas steady until the car died. Then tried to read the codes immediately. I got no 12 diag code I only got the temp light flashing. Each time it flashes I hear a clicking that sounds like the EGR. Does this make any sense? Will see about ECM replacement this weekend.

[Jrs3800]

It sounds a lot like the ECM is toast...

[theparkinggargae]

Well it wasn't the ECM. I replaced it to the same effect. I used the old prom. At least this time after I ran it (holding gas) I let it die and it threw a code 43. Apparently that's the knock sensor. Could a knock sensor keep the car from starting? I know it can effect timing, but can it advance/retard that much? I will be replacing that next but I'm thinking that if something else is causing a knock replacing the sensor won't help. Any ideas?

[Jrs3800]

Car should still idle even with a code 43, but that only indicates you have an issue in the knock sensor circuit...

So it still refuses to idle... Pull the IAC and see if you can push the pintle in a tad, and I mean a very small bit and see if the car will try to idle..

If you keep your foot on the throttle very lightly the car will idle until you take your foot off the gas correct?

[theparkinggargae]

That's what I thought. A knock sensor shouldn't keep it from running. Yes if I keep on the gas just a little it will continue to run. If I let off very slowly she just idles down until stall. Then will only start with gas slightly depressed. I will get the knock sensor anyway and check wires. I will try to adjust the iac like you said. Is there anything I can spray in there? Like carb cleaner or break cleaner or Maf cleaner? I'd think carb cleaner would be okay? It didn't look particularly dirty but I suppose it couldn't hurt.

[Jrs3800]

Don't use Carb Cleaner.... Use Throttle Body and Intake Cleaner

[theparkinggargae]

Okay I didn't clean or adjust the IAC, but I looked at my knock sensor. If I wasn't so lazy I'd upload a picture from the I phone, but the point is the wire was cut completely. I have the sensor and plug adapter, unfortunately I cannot find the other end of the wire. I expected to see it close by but I didn't. Do you know where this knock sensor wire comes from? I know it comes from the PCM but does it follow the cam sensor wiring or where does it split from the harness? It looks like I will have to find the other end and splice into it. Also what color is this wire in the harness? It looks like the plug end has a blue wire.