Starting Problems

[MonkeyFace]

I've recently had problems starting the car from cold, it turns over fine almost fires up but then doesn't quiet go. Continues to turn for a while without firing, then evenutally will splutter into life after using the throttle a bit, runs rough until blip the throttle and it will pick up and run great.

If I then turn it off it will start again straight away without any problems.

All HT leads, dizzy cap and rotor arms replaced and new dizzy.

Any ideas?

Cheers
James

[bozzzydmc]

MonkeyFace Wrote:I've recently had problems starting the car from cold, it turns over fine almost fires up but then doesn't quiet go. Continues to turn for a while without firing, then evenutally will splutter into life after using the throttle a bit, runs rough until blip the throttle and it will pick up and run great.

If I then turn it off it will start again straight away without any problems.

All HT leads, dizzy cap and rotor arms replaced and new dizzy.

Any ideas?

Cheers
James

Hi James

I find if i dont use my car for a few weeks, by pressing the accelerator down a little whilst turning it over helps it to start first time. I believe the handbook or visor label tells you to do this?. However it could be that your mixture is a little on the lean side, when was the last time this was checked ? But it sounds very much like a fuel issue rather than electrical in your case. BTW has the fuel accumulator been changed in the life of the car?

[ChrisS]

James

When cold try swapping the white connector on the Control pressure regulator with the blue connector on the cold start valve. The control pressure reg is on the LH side rocker cover at the back, behind the air con compressor. if the car does not start within 7 seconds then stop or you will flood the engine.If it does start fine then I would guess its the sensor in the top of the water pump.

[NickT]

ChrisS Wrote:James

When cold try swapping the white connector on the Control pressure regulator with the blue connector on the cold start valve. The control pressure reg is on the LH side rocker cover at the back, behind the air con compressor. if the car does not start within 7 seconds then stop or you will flood the engine.If it does start fine then I would guess its the sensor in the top of the water pump.

That would be the thermo-time switch !

Give the engine a full up first then take it from there.
Could be that the engine is too lean or more than likely too rich.

NickT.

[MonkeyFace]

Thanks for your replies.

I did try turning the key to position 2 a few times letting more fuel be pumped in and this seemed to help it start better. It can be difficult to start even after a few hours.

The accumulator has never been changed as far as I know. Mixture has never been adjusted, the little adjusting screw has not been drilled out.

I will try swapping the connectors tonight.

Thanks
James

[NickT]

sounds like it could do with a full pressure check first then take it from there.

[MonkeyFace]

I swapped the white connector for the blue one and it didn't help.
How is the best way to check the fuel pressure?

James

[NickT]

fuel pressure gauge with isolating valve for K-Jetronic mechanical injection. Similary to

Sealey Fuel Injection Pressure Test Kit
VSE210

This will then test for fuel pump, control pressure hot, control pressure cold & rest pressures and also running pressure under acceleration on the road.

Testing procedure is in the DeLorean workshop manual.

Linking pins 30 and 87 on the fuel pump relay (with a 15 amp fused cable) will run the fuel pump continuously and the car starts better then the rest pressure would probably be too low. A full test will determine if it is fuel related or if the engine is set up too rich or not.

[MonkeyFace]

I jumped the fuel pump relay to run the pump constantly but this didn't help.

When turning over the car keeps trying to start and near fires up but dies again, when I eventually get it started I get lots of white exhaust and it hesitates under accelation for a few minutes like having damp spark plugs or HT leads then the white exhaust goes away and the cars runs fine. Then if I turn the car off it starts first time and runs great.

Anything else I can test?

Cheers
James

[Barson]

Do you know if the car is running rich?

[MonkeyFace]

No don't know if its running rich. The exhaust tips aren't really very sooty but how else can you tell?

[Barson]

Well, I could be wrong, but I have an I idea that mine is running rich, because the exaust stinks of petrol - I'm pretty sure it not supposed to. Plus my plugs are all sooted up...

I think it might be my O2 sensor...

[NickT]

if your car has a cat bypass on it then set it to 1 to 1.5% co with the oxygen sensor unplugged. Plug it back in and see if the co drops to about 0.7. If so then the car is fine.

I would still do a fuel pressure test first to determine if the k-jet is set up ok.

NickT.

[stunned_monkey]

Cold starting problems on an engine that's never had the mixture screw drilled out.

- Accumulator will not affect starting from cold
- If your car starts better with a little throttle, it might be prudent to investigate your idlespeed system - this has the effect of cracking the throttles more than enough. The manual says to depress the throttle because the manual is based on the Renault manual for an engine that didn't have the idlespeed system we have.
- If the engine catches, revs then promptly stalls, the cold start circuit is working fine and you should investigate fuel pressures. Sounds to me like the cold start circuit is not working. The thermotime switch is the obvious choice and doing the plug swap methd is only useful if you understand what it is you're doing. Leave it plugged in for any length of time and without throttle it'll quickly over-fuel and flood. One other problem we see occasionally on the TT switch is when they've been replaced with the mor erobust Bosch sensors. They work exactly the same but importantly can be plugged in backwards
- Over 25 years on engines that haven't been run much, the injectors will get lazy and if the mixture has never been re-set (a good thing - we can trust it's position!) you can benefit from new ones, but I think too much weight is given to poor injector patterns, it's usually something far more obvious
- Does your frequency valve buzz? It's really quite common for us to have a car come in where the lambda system simply doesn't work. Usually related to one of two minor things and with no buzz at all (ie not powered) this will throw the mixture way out of bonk at all times. Often this has been partially balanced by someone twiddling with the mixture screw, but again, it's good yours hasn't.
- I don't like the sound of white smoke coming out the exhaust when it does finally fire - unless you're still running a cat in which case that's just steam from the warm-up cycle.

So to summarise - check if your cold start valve is actually firing. You can simply unscrew it and get someone to crank the engine (briefly!) when cold and it should spray. Next on the list would be idlespeed for me, and -then- look at fuel pressures to probably diagnose a failed control pressure reg.

[Dan Howarth]

Check your control pressure regulator. Take it apart( carefully there are 2 springs and a very small pin you could lose) and clean it all. There is a little mesh in there that can get blocked. Or you could do what i did and go to the scrap yard and get a cpr off of a Volvo with the v6 engine or the renalt and get one off an Audi. Cpr come apart in 3 pieces. Use the bottom piece off your car. the middle piece of the Audi and the top piece off the Volvo. Put it ALL back together. You will notice that your original Delorean cpr has 2 bi-metalic plates in the top section and the Volvo and Audi ones only have one. Don't worry. Slap it back on the car and start her up. The bits should only cost you about £3 and it'l only take you 10 minutes to do it. If that don't work then put your original cpr back together and ignore what i have said. It worked for me and i had similar problems as you. Give it a go what have you got to lose except an after noon on saturday pratting around with ya moter. Cool 8)