1985 760Turbo Very Hard Starting/No Start

[turbo no/go]

I should have mentioned that, but yes the distributor cap and rotor have been replaced within the last 6months, and visually inspected in last few days just while going down my checklist.
As far as the compression test, it is one of the few test I can personally do, I haven't done it just based on the fact that the car has so much power...should I still do the test?
What about leaky injectors?Do you think this could be to blame?
Thanks

[Ragman]

It never hurts to cover all the bases. I would check the compression just to know where its at. My 86 740T-M has 250,000 miles on it and still starts firtst time. The compression across 4 cyclinders is 180,175,170,180. Can't kill the red engines. Use the compression #'s for comparisons sake.

[sseir39]

Fuel pressure regulator: is the hose good, have you checked the hole in the manifold to which the hose is attatched? Is it clear. Still should start regardless. Have you checked your fuel pressure with a guage. Sounds like lack of fuel.

I am not much help.

Dick

[turbo no/go]

Yes...I've inspected the fuel pressure regulator and all attached hoses/lines like friggin' Magnum PI!
I've removed/blown air into the vacuum line, removed the return line to check for fuel...which there was. When I removed the vacuum hose from the manfold 'nipple', it had oil on and a very small amount of white smoke 'whiffed' out of the nip. Also when I copleteley unscrewed the idle screw, which goes into the manifold not far from the f.p. regulator vacuum line, and removed it from the manifold it also had oil on it???I took it out just for inspection/curiousity but I don't think the oil there is normal.
Also could this be exhaust related?manifold leak...catalytic coverter??
Thanks

[billofdurham]

You seem to have done a thorough check on most parts and have had some very good advice to help you along.

However, getting back to basics, I agree with Ragman that one of the first checks for this type of problem should be the coolant temp sensor. If it is defective then the car will be confused. Check the wiring, not forgetting the earth (ground) connection which is one of three on the intake manifold.

Again sticking with basics ensure that there is no air leak on the intake system. Check that the wiring to the knock sensor (green) and the coolant temp sensor (grey & black) have not been interchanged. Similarly with the air control valve (green, yellow/red, grey/red) and the throttle switch sensor (orange and brown).

I can't remember if the throttle switch has been checked to see if it works. It should click as soon as it opens.

You ask how to check the injectors. A quick check is, having got the engine started, listen for a click from each injector. Use a screwdriver against the injector as a listening tool. If one of the injectors does not click interchange the connector with that of an injector that does click. If the fault moves to the other injector then the fault must lie in the wiring or the ballast resistor. If the injector still does not function then it is probably defective. Measure the injector resistance which should be about 2 ohms

[turbo no/go]

The coolant temp. sensor is something I've suspected.I removed it from the engineto inspect and other than spots of discoloration on the brass I didn't see anything abnormal.I cleaned the connection area and the wire end, inspected the wiring and cleaned the ground.I suspect this is the original temp sensor, I've only owned the car for 3 years but it looks 'aged'.Is there a way to test it, or do I just replaced w/new.I should mention around the time the car beginning to be difficult to start, I found a small leak'hole'in my heater core line,just inches outside the firewall.Before I found the leak the car had gotten low in coolant on a couple of drives, and needed filling up.(1/3-1/2 gallon of coolant)It never ran hot, but on 2 occasions it was geeting close to red.Could this have affected the sensor?
Would you rule out the f.p. regulator just because it's relatively new or could it still be to blame?
Thanks for your advice.

[turbo no/go]

Ok... I decided to replace the coolant temp sensor w/a new one, but now I can't find the right one!?
Mine has the 1 prong connector, not 2.It's the original part from 8/84.
The only writing on the part is- 8/84 VDO 804/4/4 Germany 12V 120c.
The 2 prong version is supposed to work on my car, but how do I connect it w/just 1 wire?
I'm hoping you have some suggestions.
I can't find it locally or online.
Do I have to change the wiring?
Thanks to anyone who knows.

[billofdurham]

I was surprised when I checked my books and found that the sensor had two wires. I have only ever had one on any car I have owned, and that is a great number of cars.

If you can only get a two prong version one of them is for the 12v lead which you already have and you would need to run another lead to earth (ground). This is quite easy to do as there are 3 earth points on the intake manifold and this is how it is shown on the wiring diagram.

Bill.

[turbo no/go]

I found a sensor at a local parts store w/one prong, but it was listed as the non-turbo option and mine of course has turbo.I bought only because it was the only sensor available w/one prong.It was absolutley identical to my original and fit right in.I haven't been able to test it it because i found a leak in my heater core hose, right above the heater control valve.Whilst trying to take it off the nipple from cotrol valve to hose broke...meaning new heater control valve!
Aiy Carumba!!
Once I get that fixed I'll test the sensor.My question is do you think the fact that the sensor was listed as 'non turbo' means it won't work on my car.
Thanks.

[turbo no/go]

I replaced the sensor w/the non-turbo 1 prong...fixed my heater control valve leak and the car is the exact same.Still takes 15 or more tries to start it and when it starts it drives/runs normally.If I shut it off and wait just 1-2 minutes it restarts everytime.If I wait 15-20mins. or more it might not restart at all.
Idle control valve?
Leaky injector?
Hall sensor(checked/cleaned wiring)??
Battery/Alternator?
It really 'feels' electrical.Every single time I turn the key it's a real strain on the battery, which struggles to stay in the 12v range on the gauge.
It's 18 months old(battery) and has been checked so?
ANY