Engine dies out just above idle [After GTE swap]. Any tips?

[scotty]

Hey..

Done a GE to GTE swap.. the engine is running just fine on idle, and if you press the throttle quite a bit more to get the revs up right away it runs smooth. But if you just gently press the throttle, so you don't got above aprox 1-3k RPM, then it pretty much dies out. It goes weak very quickly unless you press the throttle quite a bit more to get the revs up.

Mostly it goes back to idle ok, but sometimes it doesn't and then it runs very uneven. It does however seem to run smoother when the engine gets up to temperature, and the problem with dying out almost goes away.

What can be causing this? There are no error codes.

Thanks,
Scott

 

[supraguy@aol]

Dunno without codes. Check TPS and AFM.

 

[RazoE]

are you using a GE or GTE harness..?

 

[nick88]

Check the afm, and look for boost/vac leaks.

 

[scotty]

I'm using a GTE harness. How do I check the TPS/AFM? What should I look for when I'm checking it?

I've tried to go around with some startgas on various places in the bay, but didn't get any difference on rpm. How visible is it on the boost gauge if there's a vacuum leak?

 

[supraguy@aol]

Well, at warm idle, you should get pretty close to 20psi vac.

As for TPS: http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=FI&P=101

As for the AFM: http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=FI&P=96

Save a bookmark for the TSRM- It's your main source of repair info, period.

PS- Did you connect the HAC when you did the swap? I know it can cause part throttle problems- at least on my car it once did.

 

[scotty]

Thanks!

Yes, I connected the HAC sensor.

What's a thickness gauge? See it's needed in the TPS adjustment..

 

[scotty]

I was just out and checked the AFM.. Got about 1300 ohm between THA-E2, which is not correct according to the table in this link..
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=FI&P=96

Also, is there supposed to be any tables for the other terminals? It says measure between all terminals but only THA-E2 is specified?

Still wondering what a "thickness gauge" is..

 

[89supracrazy]

Yeah. I would say it is your afm. The temp. sensor reading sounds to low. Did you check it when the engine was hot or cold. That shows around 104 degrees. The best way to test it is to have a meter that measures hertz. Mine at idle shows about 25 hertz. Measure between E1 and KS with your meter set on hertz and see if the hertz increases as you accel. Check it at idle too. If it don't move or if you don't read nothing on your meter then it is bad.

 

[hvyman]

Thickness gauge is a feeler gauge. Like what you use to measure and adjust the valves with.

http://cygnusx1.net/Supra/TechTips/engine_error_codes.aspx

 

[scotty]

Yeah. I would say it is your afm. The temp. sensor reading sounds to low. Did you check it when the engine was hot or cold. That shows around 104 degrees. The best way to test it is to have a meter that measures hertz. Mine at idle shows about 25 hertz. Measure between E1 and KS with your meter set on hertz and see if the hertz increases as you accel. Check it at idle too. If it don't move or if you don't read nothing on your meter then it is bad.

I checked with a cold engine, but has that anything to say? Are you supposed to check it with a running engine? Didn't say anything about that in the tech tips guide.

I'll check with a hertz meter soon.

thanks hvyman.

 

[hvyman]

Engine temp will not matter since your measuring intake air temp.

Afm's do not need to warm up.

 

[scotty]

I measured a few other values..

KS - E1 unlimited
E1- KS 1 500 000 ohm
VC - E1 144 000 ohm
E1- VC 154 000 ohm

As far as I know these values are way to high? Does anyone have tables or recommended values for the AFM?

 

[89supracrazy]

What I meant about the temp. sensor is what ever the temp. the afm is, that is what your resistance will be on the chart. For example, if you take the afm off of your car and stick it in the freezer for about 5 to 10 minutes your resistance will be higher. That is why I asked was the engine hot or cold. If he was running his car for a while that might be true but cold that is low resistance .Unless where he lives is 104 degrees or higher outside. What I would go by though is the hertz but check both. You can pick a meter that measures hertz for about $40.