Hot start/run issues

[Sergei]

I am basically looking to gather some more thoughts on this one...

Here is what situation looks like:
Disco 94.

Ignition: fresh plugs, dist. cap and rotor, wires. All tight. New aplifier module and coil (OE).
Air intake: all lines squeaky clean, vacuum ones replaced with thick silicone ones (thanks Joey for idea), got spare MAF to play with (thanks Will), fresh stepper motor, cone filter.
Fuel: injector cleaner was ran through, OE fuel pump is fresh (aka less than 2K miles since replacement), fresh fuel filter.
Sensors & electrical: fuel temp sensor and coolant temp sensor are pretty much new. MG fixed alternator, red top optima.

Symptoms: got issues (aka got to press pedal) with starting after getting hot. On high altitude it will sometime stall when running in low RPMs (its fun to get stuck on 11k feet at summit of some trail) and wont start for about 30 minutes - cranks but no catch.
Rest of time truck runs good, no losses of power per say. However sometime idle is hunted.

I am thinking that its either fuel injector(s) giving up or fuel pressure regulator.

However recent discovery is that sometime i am getting very hard time to operate steering when truck is standing or rolling very slow (aka parallel parking is PITA). So i am also starting to think that belt may be slipping when starting to get hot and expands too much. But would it cause stalling?

No overheating btw.

 

[neil30076]

Serg,
Before changing all the high priced parts, check out the relays. I know from experience that the same manufacturer makes the LR relays as Porsche relays, and I had an identical problem on my porsche, it that was a relay that went open circuit when it got hot. Symptoms were the car would die suddenly, or not restart for 5 - 60 minutes, then started fine. $15 fix....
Have someone crank the engine while you use a screwdriver as a stethascope pressed against an injector, if they are firing , you'll hear the click, click. Also, although you say not overheating, maybe vapor lock in fuel line.
Just a few thought.
Neil

 

[Joey]

I would say either the Relay as Neil suggests or the Injectors as you suspect. Remember it only takes one...

 

[Sergei]

Hmm.. thanks folkz. I got fuel pump relay on shelf so i guess i'll try to stick it in. Injectors i ordered yesterday so it will take a tad to get them here.

Neil - which relay was shot in your case?

 

[neil30076]

On a 94/95, i'd say K116, engine control load relay.
Its in the right footwell/wall next to the fuel pump relay.
My problem was on my Porsche, but the wiring diagrams are almost identical.
Do you have the 94/95 wiring diags? If not, email me and i'll send you the pages.
Neil.

 

[Sergei]

Yeah i got electrical manual , thank you.

So engine one, eh.. Gotta check if its "general purpose" or specific one. I should have spare "general purpose" laying about.


Thanks for idea!

 

[Sergei]

Ok. So i replaced both silver relays (one with generic relay and one with OE one, that i had for spares). No go - same symptoms.

So i started to take things apart - swapped plugs for second set i had. Took out and swapped coil back and fourth - nope. Played with pump..

So i almost gave up and decided to wait for injectors to arrive, when all the sudden i lifted distributor cap (in some insane attempt of finding something) and viola - there is was...

New bloody cap, made by bloody italian maker... Had no issues on side contacts, so i had not spotted it at first, but then i started to look closely at middle contact (one that goes to rotor) and it did look suspicios - so i dug out old cap (kept it just in case) - and damn thing was like half way eaten through. So i did some research on subj and turns out that Italian Made Distributor Caps are famous for those issues. Apparently it was literally "shaved" by rotor so whenever cap got really heated up - space between rotor and contact was increasing (plastic expands under heat) and hence all those idiotic stallings and hot start problems.

I put old cap in - and old good issue with stalling at some stops came back, but truck starts right away. So i ordered BW made cap, and driving like that..

Morale - beware of those italian crappy caps..

(still think me got leaky injectors, but thats different story).

 

[ShaunP]

Hard staring when hot is normally the fuel temp sensor, the engine floods. Cheap as fix. Fuel temp sensor leans the ecu on hot start only.