75 Turbo

[grale]

Hi

I have some problems with ma 75 Turbo.
The first one is it can´t hold the idle speed.
When cold, if I start the engine it runs ok, with an idle speed of 900-950rpm, but in two minutes, when it stars to get hot the idle speed starts to drop, it starts to go up and down (500-900). It does that 4 or 6 time and it cuts…
After it cuts, I start the engine and it starts ok but after it started e cuts…
Is it the idle speed that is not tuned?
How can I check and fine tune the idle speed?

Second, I don’t have Turbo pressure on the dash. What can I check?

Third, I also don’t have temp on the dash. Can some one tell me where is the sensor?

Regards

Carlos Oliveira

[BigSwede]

-Coolant temp sender probably broken. it's the one with a blue connector on the inlet manifold.

-Check the ground strap from the intercooler, it's very easy to forget to put it back on after working on the intercooler. Without it the pressure sender is not grounded and does not give a signal to the meter in the dash.

[grale]

Thanks for your replay.
I´m going to check that.
Can you tell me how can I tune de Idle speed?

Regards.

Carlos Oliveira

[hfintegrale]

Hello Carlos. Look at this picture:



If you turn the screw off, the r.p.m increases.

Important!!! Before you will need check the correct ignition timing.

Greetings.

Julian


1987 Alfa 75 1.8 Turbo Evoluzione
1988 Alfa 75 1.8 Turbo America

[grale]

Yesterday the car came from painting, and adjusted the idle speed to 900rpm and now it is fine.
Thank you for the info...

Another thing that I tried yesterday was the AC. I think it is working fine, as I ear the compressor running. The problem is that with de AC on, the idle speed goes down to 600rpm (+ or -).
Is there anything to correct that?

Regards

Carlos Oliveira

[hfintegrale]

This is not normal. The LE2-Jetronic increases the r.p.m. when the AC is working (idle speed about 800 r.p.m.), but the problem isn't important. Check the AC wires.

Greetings.

Julian


1987 Alfa 75 1.8 Turbo Evoluzione
1988 Alfa 75 1.8 Turbo America

[grale]

Since your reply, é tested de AC every day and sometimes it works like you said (about 800 rpm) anda sometimes it works at about 600. Sometimes I try it and it´s working fine (800), then I switch off, then on again and it idles low. Then I switch off and on again, and it´s normal again...
Strange...
It´s an Alfa... lololol
Like you said it´s not important...
I have another question...
I bought this car short time ago, and it has no "inspection" and insurance, so I can´t drive it on the street.
And the car was in bad shape, it had some rust and needed painting. Now it´s repaired and painted.
At the same time I replaced the exaust, because from the end of the turbo to the end of the muffler it was complitely rusty.
It had a pipe from the turbo to a oem direct rear muffler, and because of that it made a lot of noise.
At the same time, when at idle, if I pressed the gas and the engine reached about 4500rpm and I release the gas it made some small backfire. I thought it was because the system was "direct"...
But now with the normal exaust system (2 mufflers - Middle and end), it does de same thing...
Is this normal in this model?

Regards

Carlos Oliveira

[hfintegrale]

Yes, it´s normal. In my car, when the r.p.m are high, and I put the throttle off quickly, the exhaust shoots a bang! like the bang-bang in a world rally championship car. It´s very useful when other car is too much near in the highway

Check the gasket between the exhaust manifold and the turbo. If this gasket isn´t perfect, this is the problem.

Greetings.

Julian


1987 Alfa 75 1.8 Turbo Evoluzione
1988 Alfa 75 1.8 Turbo America