930 wont start when hot..please help

[Kiwi930]

I have an 86 930 which starts perfectly (maybe too well) when cold. Runs like a rocket, then when you shut her down it will start straight back up no problem. Leave it for 30 seconds, and I will have to wait another hour until it will start. It has an Andial fuel enrichment system/IC, MSD 6AL, AM heat exchangers , Upgraded turbo, and has an adjustable boost tap. With this closed it will run .9 bar, but feels best at 1 bar. I have done the accumulater/filter, tested the pumps, replaced the overboost relay,done the plugs,IC seals,Coil (MSD). The car had an incompatible Bosch coil on it when i brought it, and it ran like a dog...now it seems to go far better. I have progressed in diagnosing the problem to the point of realising that if I donnot give it any boost whilst driving, it will restart every time. If i do, i get this problem. It has an Andial overboost switch, and when i disconnect the white wire running to it (The andial unit has two wires, the white wire i am referring to and an earth wire), the car will start no problem.
When it doesnt start the ignition on power source to the FP relays is extremely weak, and it is getting no spark.
I have had to replace the Number 1 FP relay,overboost relay and the relay switching the Andial.

I donnot have a CIS tester, and am in Switzerland (the land of stupendous labour costs).

Thank you in advance for your advice, knowledge.

Adam

[Noah930]

Is the speed relay under the driver's seat still connected? I had a similar no-start problem on a warm motor in my stock car, and in the end it turned out to be this part that needs to be resoldered.

[Kiwi930]

Thank you for your reply Noah. No it isnt. I had assumed that with the MSD/Fuel enrichment it was no longer needed? Did yor problem only arise after you had 'boosted' whilst driving? Thanks

[GUT]

I don't think I can help with your problem but I feel your pain on the stupendous labour costs, being in Australia.

Given it works when you don't boost or you disconnect the overboost switch, maybe it's a problem with the switch? Take the switch out of the equation and it works. Now of course, I don't know how these work exactly but they're meant to cut the ignition right? Can you swap another in for a test? Is there any way to test the switch function?

Good luck with it.

[klefroid]

I had the same... now I use a button inside the car which activates the cold start valve... very happy

[Kiwi930]

Nice, a button to activate the cold start valve....Worth a shot. Thank you and will get back to you on Tuesday with a result....fingers crossed a good one!

[Kiwi930]

Hey Gut, thats exactly where i was up to in my diagnosis. Unfortunately the Andial fuel enrichment runs a different switch, and am scared of trying a factory one. I would try to ring Andial America....but they no longer exist!. Then of course i became confused after reading about the infamous WUR problems, and wondered if the internal heating element may have been my problem.
If i disconnect the over boost switch, do i then lose my fuel enrichment? If so it will be running so very lean, and risk blowing the engine.

[heliolps2]

Hello

Usually its the fuel accumulator that's the problem, If it starts when cold, its most likely the problem

[klefroid]

In those old Ford Cars with CIS was a timer. When you tried to start the car longer then few seconds the cold start valve became activated when the car was warm. I changed it all without a result. New accumulator and new WUR injector blocks and no leaks at all. Found few very small ones and after I fixed them my engine was holding pressure for minutes while testing for leaks. When you have the button you should be able to hear the klikking sound when pushing it. It is nice to have this inside the car. Helps big time and you can always remove it when you found your problem. Or leave it there just in case.It is even a good diagnose tool. When it does not start and you activate the cold start valve only for a sec or so, that would mean you have an air leak or problems with your WUR. When you need to push it longer to keep the car running fine, then you need to look to vaporlock or so I guesss???... good luck

[aerochip]

Any idea what the fuel pressure is doing? My warm pressure lowers significantly under the same circumstances you are talking about. I can still get her started, but she isn't always real happy about it. This may be causing some problems for you with very low fuel pressure on a warm motor.

[Kiwi930]

Thank you AeroChip... I may have to buy some CIS gauges me thinks.. Accumulator was my first job Heliolps2...did nothing, bugger it.

[T77911S]

Originally Posted by Kiwi930

When it doesnt start the ignition on power source to the FP relays is extremely weak, and it is getting no spark.
.

Adam

this is where I would start. no spark.
you have a delayed action relay that provides power to the CD unit. I would bypass that and see if it has spark.

how do you know power is weak to the relays.

[SweetWaterSurprise]

I'm having the exact same issues in my car with nearly the exact same setup as you Kiwi930

[klefroid]

Some people asked me how I did this setup for the cold start valve button.
My skills are not as good as others here but I try to explain (works for me)
If someone has more skills please be my guest. I'm not going to far into details to keep it easy.

In this picture you see the sensor that closes when the engine is cold.




Here you see how the cold start valve gets it's power.
Two way's to manipulate

1: Just take off both wires from the sensor and extend those inside the car and fix them to a push button = When you turn the ignition key (engine firing ) while pushing the button the cold start valve is activated until you let go your ignition key or button.

2: Bridge the sensor (cold start valve always gets mass/ground)
place a push button inside the car and go with those two wires to your starter.
on your starter you see two thin wires. one going to the CSV and one going to ignition key. take off the one that is coming from the CSV (if you take off the wrong one you car does not fire) so you need to connect that wire to the button. Connect the wire that is left over to the positive source on your starter. (Big wire m8) done (you can always at a fuse close to the starter to keep it save)

Be sure to disconnect your battery before doing all this!

I did the second option (love it)

Good luck

[bpu699]

Mine did this when the AFR was too lean at idle... Cold it was fine because of the cold start valve... hot, it would take several turns of the ignition and some poking to get it to start...

Try to simply turn the idle mixture screw 15-20 degrees clockwise... may fix your issues...

[Kiwi930]

Thank you for both the above replies! I will atempt the latter first ( of course) if a simple turn of a screw fails. i will install that switch. Thank you once again.

[Kiwi930]

Painful huh? Almost has me at the point of turning to EFI! I hapoe and pray the above work, please let me know if you have had success attempting the hot tips mentioned

[T77911S]

I wouldn't install the switch.

fix the problem first of all.

second, these cars are really nice cars and the value is going up. hacking into the wiring, unless it can be put back to original, is not a good idea.
trust me, I have a nice 930 with really nice wiring and it just makes me smile every time I get in there and see it.

[klefroid]

Originally Posted by T77911S

I wouldn't install the switch.

fix the problem first of all.

second, these cars are really nice cars and the value is going up. hacking into the wiring, unless it can be put back to original, is not a good idea.
trust me, I have a nice 930 with really nice wiring and it just makes me smile every time I get in there and see it.

There is no need to cut in any wire! you can keep all original. you can re-do in 30 min.
It does not make you smile when your car does not start, people watching and laughing. One time I used start pilot and my air-box exploded while trying to start the car... metering plate also broken...
The good thing about this is that you can hunt for the problem and still using your car... once you find the culprit, just go back to original wiring.

[Rawknees'Turbo]

Klefroid, that is an excellent idea, and not a thing hack about it.