Stumble at light throttle!

[3Bar_Mopar]

Today I finished swapping on the head from my '89 turbo van to my '90 Daytona.... I had trouble starting it when I was finished and my timing turned out to be way off. I fixed that and the car started up fine and idled smoothly for a minute or two, then stumbled and eventually died.

Every time I'd start the car after, it would start and idle exremely smooth, but like clockwork, after a minute or two it would miss, stumble and die.

After awhile it would idle all the time just fine, but light throttle would cause a pretty bad miss. It even died trying to take off. No throttle or heavy throttle and everything is fine.

What I think has happened is that the van had a temperature light instead of guage. My Daytona had an actual guage....

Would the coolant temp sensor be causing the stumble?? My temp guage stays on full cold and never moves now. A/F reads full lean when it stumbles.

[cordes]

Any codes? Could be map related I suppose.

[3Bar_Mopar]

Any codes? Could be map related I suppose.

No codes. The MAP is installed correctly and worked fine before the head swap. I never touched the MAP other than to pull the vac line from it and put it back.

[cordes]

No codes. The MAP is installed correctly and worked fine before the head swap. I never touched the MAP other than to pull the vac line from it and put it back.

That is a rough one. I had the same problem after a head swap, but I found out after much trouble, that I had put the wrong vac line on the map, and it would run, but not very well, and it would die after a few minutes.

Good luck.

[3Bar_Mopar]

I have the MAP sensor running off it's own line from the intake manifold....actually the same barb that I used on the old head.

For some reason I keep going back to thinking it's the coolant temp sensor. The van the head came from only had a temp light...the car the head is on now had a guage. The guage stays pegged cold 100% of the time now and I think that (van) coolant temp sensor is causing problems with the Daytona's electronics.

It idles silky smooth now....when you come to a stop it idles so smooth I thought it died. It's just a bad, lean stumble at throttle tip-in. If you hold the gas peddle at a little less than a quarter down, it will continue to stumble and miss....let off it's fine.....give more gas and it's fine.

[TurbododgePirate]

If the temp gauge is at full cold, all the time I woudl think you woudl have to check the thermostat and the temp sensor. But sounds like temp sensor to me.

[Clay]

You have the map sensor line run throught he map solenoid right?

[3Bar_Mopar]

You have the map sensor line run throught he map solenoid right?


Yeah....I also changed temp sensors and no change. Although I get hot air through the heater, the guage does not move..
I changed plugs and ran a new line to the MAP sensor.

I had to change the harness to the injectors becuase the van head had different plugs. I grabbed the injectors harness from the old Daytona head and put it onto the van injectors. Could this be causing the problem?

I may grab the injectors from the Daytona head and try to use them.

[CDNTurboZ]

I am having the same problem right now as well(just did a head swap) I really want to see what the outcome is here:thumb:

[Clay]

What engine is in the daytona? The know the van was a 2.5, is the daytona a 2.2?? that could cause a problem.

clay

[Subliminal]

This may be a dumb question, but cant you just swap the sensor across from one head to the other to rule that in/out as the problem?

[t3rse]

does the guage not read from the temp sensor in the front of the head? my computer reads the coolant temp from the t-stat housing. my guage doesn't work, but the computer is getting the right information.

the computer richens the mix on startup, so it might run fine cold and die if it's getting leaned out after the startup cycle. check your spark plugs or a/f guage if you have one. another stupid one, but make sure you have enough coolant in your radiator: you sensor wouldn't be able to determine the temp if above fluid level (duh, and obvious and i don't mean to insult your intellegence).

[Clay]

There are two sending units on the head. The one on the t-stat housing is for the computer, the one next to the a/c compressor is for the gauge.

clay

[3Bar_Mopar]

This may be a dumb question, but cant you just swap the sensor across from one head to the other to rule that in/out as the problem?


I did that...see above post. The problem remained but I changed plugs and the stumble has gone away gradually.

The coolant was full because when I changed CT sensors, coolant poured from the hole in the housing. Also I purged the system and the coolant level was rock solid in the rad with the T-stat open....no bubbles.

There is no stumble now apparently.


Clay...the Daytona engine is also a 2.5...

[3Bar_Mopar]

Apparently everything is fine now! The only thing I'm having trouble with is my temp guage don't work still. I have no idea why!

I had a flare from 2nd gear to third (automatic, duh!). but found that to be the kickdown cable fell off....fixed.

I still get an occasional stumble or slight miss, but for the most part it's gone. The van used to take longer period of cranking to start.....the Daytona now has the same deal. I think it's the injectors. I have the Daytona injectors and I may swap them in.....maybe they have something to do with the slight, very occasional miss.

If i can get the temp gauge sorted I'll be fine.

The engine sounds way different now, it's weird! The turbo sounds almost like a police siren compared to the whistle of the Mitsu.


Big --- intercooler is next to go in!!:thumb:

[GLHSKEN]

It should sound that way with a larger turbo... I love that whistle

[cordes]

I would replace the sender if it is not too expensive because it will be easier than tearing into the dash, and if that does not solve the problem, I would check to see that you are getting voltage to the gauge, and that there is a good ground there.

[Subliminal]

I did that...see above post.

Sorry man...reading comprehension..she's a -----! ;)

[3Bar_Mopar]

I would replace the sender if it is not too expensive because it will be easier than tearing into the dash, and if that does not solve the problem, I would check to see that you are getting voltage to the gauge, and that there is a good ground there.

I'll probably just grab the sender from the Daytona head. I doubt it's anything else since I haven't touched anything other than swap heads and it worked fine before.

Also...I do have a dumb question and I should be way past this, but my brain is farting....does the little "button" thingy on the distributor cap go to the front or to the back closest the engine? I can't remember for the life of me. It's in the front now.

[3Bar_Mopar]

Sorry man...reading comprehension..she's a -----! ;)


Ahh...that's OK! :thumb:

[cordes]

I'll probably just grab the sender from the Daytona head. I doubt it's anything else since I haven't touched anything other than swap heads and it worked fine before.

Also...I do have a dumb question and I should be way past this, but my brain is farting....does the little "button" thingy on the distributor cap go to the front or to the back closest the engine? I can't remember for the life of me. It's in the front now.


I honestly don't recall, I just line up the notch in the bottom of the cap with the coresponding rise in the piece under the rotor.