So my 89 started acting up. The car was idling great then all of a sudden the cel started blinking and the car was missing, back fireing and black smoke coming from tail pipe. Now it doesn't hold an idle at all and no codes are stored.

I've checked for vacation leeks and even pulled the runners and checked the gaskets there. All was good. I checked the timing and when I disconnected the esc connector it started to idle good again And the cel stopped flickering. Not sure where to go from here, any thoughts?

 

Ignition module in your dizzy maybe. I think most parts stores can bench test those.

 

It could be, I'll pick one up along with a cap and rotor just to cover the bases.

 

alright so after a new cap, rotor button, plugs and icm its still missing and back fireing and the cel is still flashing, but not setting any codes. if i disconnect the timing wire it runs good and the cel stops flashing and i get the code 42 like it should. but when i plug it back in it starts missing again. where should i go from here?

fuel pressure is 45lbs.

 

I think flashing usually means a misfire. Since it runs better and doesn't seem to be misfiring without the ECU adjusting the timing and you've covered everything else...perhaps you have a faulty ECU. Another possibility is a clogged cat.

 

What was the timing at when you checked it? What happens to the timing mark when you plug it back in? I've heard of this problem being a bad ECM problem before. Or the PROM isn't fully seated in the ecm.

 

Timing was at 6* and it didn't move at all when I plugged the connectors back together.

 

Oh and no cat just a muffler

 

When you reconnect the est wire and restart the car it still reads initial timing leads me to believe either you have a evm problem or bad circuit for controlling the timing. Search check engine light flashing on thirdgen and a few threads will help.

 

ill try tracing the est wire to see if there is a brake or short in it.

i checked the junkyards around but no one has an ecm, they can get one but its 130 bucks and no garentee if it works or not. i might be better off just getting a remand one just not sure yet.

 

I had to put a reman computer in my 91 not that long ago. I don't think it was $130 for a reman with a warranty. Your salvage yard must be delusional on their prices.

 

yea they all want crazy prices for everything. i priced a rearend and for a 9 bolt they wanted 800 for it.

 

so i tryed to do some data logging today and with the est connected it wouldn't connect unless i revved it over 1500 rpm, thats with winaldl. with the est disconnected it connected fine at idle, which has me thinking it might be the ecm.

i checked with napa in town and they can get a reman ecm for 170(canadian). so i think i might go with them, at least that way i get a warranty. i'll still check some other part places around but they'll all prob be the same price.

 

Still waiting for the new ecu to come in so I decided to trace the est wire. I could follow it to the big plug on the distruter on one end and back inside the car at the other. From the ecu I traced it 6 or 8 inches to where it gets soldered to 2 wires, 1 goes out under the hood and the other and the other goes inside the dash somewhere.

Where would it be going to under the dash?

 

http://austinthirdgen.org/mkportal/m...ine_wiring.gif
The est, tan/blk, should go from the ign module to the ecm pin D5. I think it's through the C207 connector and P/S fender. I don't know why it would go anywhere else. Sure it's the correct wire?

 

im pretty sure its the right wire, i took some pics of it
this first one is showing where the 2 wires are soldered together,



this one shows one wire going out under the hood while the other goes up to a connector under the dash



this is the connector it goes to and from there i lose track of it



any thought on where this might go?

 

I'm not sure. I'm sure someone knows off the top of their head here. My guess is the ALDL. Check it on your car. I don't know of anything else that might be able to utilize it.

 

Well a new ecu didn't help much. But now if I take the memcal out and reinstall it it works good until I turn the car off, then once restarted the fan will start as soon as the key is turned. And I can't check for codes until it remove the memcal and reinstall it.

Could it be a deficitive remaned ecm or the memcal going bad?

 

What happens if you put the old one back in?

 

If sounds like you have timing/electrical issue but just out of curiosity...if you pull the vacuum line on your FPR, is there any indication of gas in the vacuum line?

 

i had to trade in my old ecm for the new one.

i haven't seen any fuel in there or smelled any, but i do loose pressure as soon as the pump stops. but if i pinch off the return line the pressure stays up until i relive the clamp.

 

Try and source an ECM on the classified boards. I'd send you one but I don't know if I have it still or if it works...I'll have to check.

 

well i finally got the old girl running good. i gotta give a big thumbs up to nappa and their warranty, took the old ecm back and just gave me another one.

thanks for all the help folks i appreciate it

 

So it was the ecu causing all your issues?

 

apparently so, it was the only thing i did different