DIS Module questions

[scotts90ranger]

I've worked many of the issues out of my engine, but one issue persists. The issue is poor drivability on a hot restart, very poor power and misfires but no related codes, the issue with not having codes is that I have a '86 ECM with a '89 ignition system so there aren't diagnostics for it... I'm running 1 coil pack and 4 plugs and has been running for 2 years

Both of the ignition modules I have behave the same, the crank sensor is fairly recent and I've tried a different coil pack also along with a different identical ECM.

It also has an issue where it crapps out over 5psi boost, but that's for another forum, this issue caused my truck to roll on a dune...

any ideas? I'm going to the JY tomorrow hopefully to get a few parts to repair after the roll, hoping to find a spare DIS module

 

[Moreflying]

Run a compression check to start. As far as crapping out with 5 psi....check the air fuel ratios. Obviously you have to have supporting mods for
the boost.

 

[scotts90ranger]

everything is appropriate for the mods, it's a '86 turbocoupe ECM and engine block with an '89 ignition system, last time I did a compression test it was 120 across all 4 cylinders (8:1 compression). The only codes that come up on a test are for the EGR which wouldn't explain any of my issues.

 

[kimcrwbr1]

Maybe grab some sensors for a 87 if you can ECT, IAT,TPS, egr position, kinna sounds like when you stop the engine hot it rises the temp and the computer trys to compensate but cant, how is the engine temp and does it raise temp shortly after the engine is shut down possible coolant issue if there is alot of muck in the block not allowing it to transfer heat properly. I noticed on my 2.8 it no longer gets as hot shortly after the engine is stopped. I pulled the water pump and shot high pressure water in and got alot of crud out same with t-stat.

 

[tomw]

Have you determined if the hot misfire is due to ignition problems or to fuel problems. I would think it possible the older ECM may be unaware of the engine temp, and be providing too much fuel, causing fouled plugs. The turbos were equipped with a MAP sensor for some years, and that could cause incorrect fuel mixture if it were broken. I know they can cause an unstable idle if defective because they don't know how much fuel to supply.
On the other hand, is the DIS module located such that it is not being overheated? Are the grounds all clean and tight on the coil?
tom

 

[scotts90ranger]

the problem is more engine compartment temp related than engine temp as with this radiator it doesn't run hot. The turbo engine uses a Baro sensor not a MAP (same sensor though), which is a good call as I have it located about 1' above the engine, could be overheating and causing an issue, apparently it is only looked at at startup...

the only sensors different from the '85/86 turbo engine and the '87/88 turbo are the IAT that's added, and a different vane air flow meter, I do have enough parts in the garage to swap to the 87/88 setup but want to work out bugs first, it involves some wiring changes and plumbing for the different size VAM

I don't have the EGR connected right now as I don't have all the parts to make it work... valve is currently broken so I added a block off plate.

The last time I pulled out all 4 plugs they all looked decent and the same. I am pretty sure that it is ignition related as it doesn't ping, just misfires.

Once I get a new seat belt and the drivers seat back in I'll drive it around some more and get it fresh in mind.

 

[tomw]

My brother's turbo had a MAP, and he used to remove the hose to the intake. I think it was used to limit boost as it seemed to have a lot more hp when he pulled that hose. I guess proper terminology is a BARO sensor in this application, but I thought it was the same gizmo just being used differently.
I also found the 'hairs' on his spark plugs after we ground the valves. They were platinum plugs, and the hairs were the electrodes.... which I proceeded to knock off. Old eyes. It didn't run too well after that. Guess the gap was too big. It was hard to start, so maybe you have something similar going on? I have been warned about the bolts for the DIS and EDIS and coil packs. It seems there are more than one ground for some of these boxes, and thus all bolts have to be installed to be sure to get proper ground. Of course, I won't be my paycheck on that 'fact'.
tom

 

[scotts90ranger]

I'm running autolite copper plugs, I heard platinum's don't work the best in turbo engines...

The sensor your brother was disconnecting was the boost controller, it's a solenoid that controls the air flow to the waste gate. All turbo 2.3's set up from the factory used a baro sensor. A MAP sensor would be better I imagine but it wasn't my decision set up right a MAP sensor will do both...