Warm start/re start issue

[xrqtr]

I've read what ever came up in a search but nothing really seems to be the same as what mine's doing, it starts fine when cold (usuaully a couple of goes) but once it's been sitting a while after it's been shut down it just won't go, cranks but no fire. The fuel pump still goes so it's not that, I've replaced the filter and accumulator. I have noticed though that the pump does prime for a lot longer when it won't start, if I spray Start Ya Bastard down the throttle it'll fire until it burns the ether off then dies again.
Definitely fuel from everything I've tried and noticed so will be checking fuel distributor/injectors next, but just wondering if the fuel pressure reg up front near the throttle might be causing it at all. I've read elsewhere that the small filters in the inbound fuel line to the distributor can sometimes cause issues so will remove it for now to see if that makes any difference.

Just going through a process of elimination for now as I don't want to spend too much as I just need to sort it out for rego and will be getting an engine swap in the not too distant future.

Any thoughts on possible cause/s would be greatly appreciated.

Thanks in advance

[xrqtr]

The other thing I was wondering is where does the fuel distributor get it's signal from, it would no doubt have some kind of solenoid controlling flow which would need to get a signal from somewhere so where does it get it's signal?? That way I can check for any overheating electrical circuits or even just a trial and error replacement of relays and what not.

[Ivanerrol]

KE system is constant flow.
No electronics in fuel distributor apart from EHA which only controls mixture governed by O2 sensor.

Fuel pump relays are known to cause problems after warmup.

Crank sensor also has issues when warmed up.

Leaky fuel injectors also cause warm startup issues.

[xrqtr]

Might be trying this next as well

https://www.youtube.com/watch?v=s06-Yd-iTtQ

[xrqtr]

KE system is constant flow.
No electronics in fuel distributor apart from EHA which only controls mixture governed by O2 sensor.

Fuel pump relays are known to cause problems after warmup.

Crank sensor also has issues when warmed up.

Leaky fuel injectors also cause warm startup issues.

Thanks for the reply, the crank sensor can pretty much be deleted as it's definitely fuel not spark unless it also triggers some kind of fuel supply valve, the injectors are cheap enough so might even replace them, the relays I haven't tried but are on the list of checks

[Jelfes]

I've the same problem on 2 of my 190e's. Both times I had hot start problems and occasionally the engine would just stop whilst driving. Both times it was the fuel pump relay located behind the battery and when I replaced the relay and the problem went away.
If you pull out the relay and carefully remove the cover it will have a burning mica smell if it's faulty or corroded solder points that can carefully be resoldered with a small pointed solder iron.
If you car is starting ok when it's cold then it won't be a clogged filter in the fuel distributor.
The relays are quite expensive to buy new from a stealership, so you might want to see if you can get a cheap one from a wrecker first or buy a new after market one from eBay. Make sure you get the same part number as your original as there are a lot of different types with kick down stamped on them.
Another thing that might be happening is a leaking EHA valve located on the side of the fuel distributor. If it is leaking you would normally have a fuel smell associated with the leak or check if you have any fuel stains from the leak around the inlet manifold. EHA valves tend to get hair line crackers in the body around the 2 internal green o'rings after years of use.
As for injectors. You can alway pull them out and them leaked checked as they are not cheap either. If you end up replacing them, make sure you also replace the injector seals.
Hope this helps?

[xrqtr]

Thanks Jelfes, ye I cleaned up the contacts on the OVP and ECU but didn't realize the fuel pump relay is there also, trying to find a workshop manual, as it actually stalled on me yesterday and had some contact cleaner so just started checking connections and cleaning. Anyway kept on cleaning connectors today and tried to adjust the air flow sensor but it seems to be a bit dodgey, not sure but the screw feels like it's f'd by someone previously, which kind of makes sense as the idle adjuster screw on the throttle linkage was messed with and broken as well. Anyway now she won't start at all I'll get back into it tomorrow LOL. Checked spark and good, fuel pump primes but it's weird as it won't even fire up with 'Start Ya Bastard'

I have actually got her running better though, prior to this current kerfuffle, the car had been sitting for a number of months with the previous owner and fuel economy was pretty crap (about 180km to half tank) so ran the fuel down to warning light then put in a few cans of Liqui Moly injector cleaner and let it run for a while, gave it a few good blasts up the road to get good high fuel pressure, anyway got mileage up by about around 40-50% after a fill got almost 200k's on the first quarter to three quarter tank.

[KimB]

Have you checked the distributor cap for cracks? This causes the sort of issues you are having.
Cheers
Kim

[xrqtr]

Hiya Kim, ye took it off today as it was definitely spark not fuel, anyway I didn't know they ran a wet dizzy system lol, might have a leaking seal again an issue of a car that hasn't been started/driven in some time. The cap does need replacing as does the rotor button so will be getting onto that this week. The earlier issues did not present as spark but was always on the replace list as usual with any second hand car purchased.

Anyway I pulled the plugs out earlier and surprise surprise wet, so I left them out for a while to dry off the chambers, the plugs were quite filthy which was surprising seeing as I replaced them not long ago but might have been the injector cleaner that burnt them up so I'll clean them up tomorrow. I actually put them back in after a few hours and it almost started so obviously we have spark but I pulled them out again and I'll clean them up tomorrow.

Can anyone tell me the resistance across the primary and secondary points for the coil and also the factory leads as I will also check that tomorrow, I want to check this as when I was checking for spark across the leads it did seem like rather weak spark, orangey/brown color as opposed to blue/white so that might also explain the dark plugs.

[xrqtr]

OK well, it's either the air flow meter or the fuel distributor, pretty sure the air flow though, it's pouring fuel into the chambers like a torrential storm, gone through almost a quarter tank just from cranking it and the couple of times it did manage to start the exhaust was thick black smoke and wouldn't run unless at WOT. But when I keep the flap slightly open by jamming something in it does nothing, I tried to check the duty cycle today but seems to be stuck at 30% and I can't seem to get any kind of adjustment out of it.

Anyway more money

[Jelfes]

If it's pouring fuel into the pots, it's most likely a ruptured diaphragm in the fuel distributor.

This is also probably why you can't adjust the duty cycle.

[xrqtr]

Ye I was thinking it might be either something to do with the distributor, fuel pressure reg or air flow

I'm also wondering if perhaps the pin/plunger is stuck fully open and it's just allowing fuel to pour through.

[xrqtr]

OK narrowed it down to the governer on the fuel distributor, does anyone have any resistance values or a test procedure for the EHA valve??

[scorchi0]

OK narrowed it down to the governer on the fuel distributor, does anyone have any resistance values or a test procedure for the EHA valve??

This should sort you out:
http://www.w124performance.com/service/ ... 3-0121.pdf

[kiqnkf]

Check the rear-most temperature sensor in the head. looks like this:

http://www.ebay.com.au/itm/Mercedes-86- ... SwGvhT~Cgl

they are a prick to get out.
they are easy to break.
they are fragile as a china doll.

you have been warned!!!

This is the one that tells the computer the engine temp. Also the OVP relay causes fuel issues (I unfortunatly know this from personal experience, in the last few months)

Can't be ignition system if the "start ya westie" (obtained with a little artistry for my mates turbo westfield that usually gives him grief) gets it to run.

[xrqtr]

Great thanks, although just going through a couple of the diagrams there is also a 'low rev fuel cut off microswitch' has anyone ever had problems with this??

[Ivanerrol]

Your warm start valve maybe faulty if fuel is pouring in.

But then again.
The KE systems is also called the CIS - constant injection system.
The fuel system will pump fuel into the engine as long as it's turning over. If the ignition system is not firing the cylinders the post will appear "wet".

Essentially there is no idle adjustment on the throttle position. The throttle position sensor and flap are preset to set adjustments and this determines the idle speed in conjunction with the idle control valve.
The EHA only sets a leaner or richer condition according to response of the O2 sensor.

[xrqtr]

Checked voltage at EHA at 4v with key in ON position but meant to be around 7.9, so either OVP or bad O2 maybe, used a 9v battery to shut off EHA valve and it started fine but then shut off due to non varying voltage. More fun ahead

[xrqtr]

Aaaaaaaand the saga continues, LOL I replaced the whole afm unit and it seems to have done one job but now there seems to be a vac leak somewhere......... *slaps forehead* .......

[Ivanerrol]

Usual suspects when changing AFM or throttle body are the hoses to the Idle air valve.