Project Car / Motorbike thread. Let's see 'em.

Haakon

Haakon

has an accommodating arse
Flow-Rider said:
Check that base idle is right then see where the timing is, TPS is in the right range at idle?
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Not clear what youre saying. Base idle do you mean the target idle? Its an electric throttle body, so no TPS - according the laptop the ecu is seeing the throttle pedal as closed and is modulating the butterfly trying to hold the idle speed.
 
Haakon

Haakon

has an accommodating arse
Mattyp said:
Start engine, spray throttle body cleaner or similar everywhere, if revs increase you have a leak there.
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yep, done that. except for the bottom on the lower manifold gasket due to access. The engine was sitting outside wrapped in plastic for several months - ive never heard of pressed steel gaskets failing from rust and sitting around, but willing to be educated....
 
Haakon

Haakon

has an accommodating arse
Oh yeah - it idles ok from dead cold for about 10-20 seconds before it starts to hunt. A higher idle obviously, but made me chase fuel and O2 sensors for a while - closed and open loop differences…
 
Flow-Rider

Flow-Rider

Burner
Haakon said:
Not clear what youre saying. Base idle do you mean the target idle? Its an electric throttle body, so no TPS - according the laptop the ecu is seeing the throttle pedal as closed and is modulating the butterfly trying to hold the idle speed.
Click to expand...
There should be a certain gap at the throttle body, and there will be a certain percentage of the throttle butterfly in a closed or home position where the computer recognises the car is at idle. If it's a fly-by-wire probably all fixed but I don't have any access to specs for these things.
 
Dales Cannon

Dales Cannon

lightbrain about 4pm
Staff member
With such an erratic idle you might not pick up cleaner being ingested try wd40 and just look for a period of smoother idle. Looking at the charts again the manifold pressure is driving the other inputs though it could be injection. If it worked fine before and you didn't pull the manifold look for misplaced or kinked vacuum lines. It has to be simple if it was ok in the other car.
 
Cardy George

Cardy George

Piercing rural members since 1981
Haakon said:
Oh yeah - it idles ok from dead cold for about 10-20 seconds before it starts to hunt. A higher idle obviously, but made me chase fuel and O2 sensors for a while - closed and open loop differences…
Click to expand...
10-20secs is probably too short for what I'm about to describe, but hear me out, it might be a clue.

The Kingswood's carby is made up of three plates, top has choke and air intake, second has float chamber and circuits, bottom has throttle butterflies. When it's stone cold it idles fine, when it's fully warmed through it idles fine, but in that mid-way, not warm but not cold period the plates would warp and it would dump droplets of fuel in and either stall or try blow the muffler out of it.

I know yours is EFI, but maybe something like that is happening. Something might be changing shape and letting air in. Would need to be close to the cylinders to be heat effected that quickly tho.

I also like Dale's latest suggestion
 
Haakon

Haakon

has an accommodating arse
Dales Cannon said:
With such an erratic idle you might not pick up cleaner being ingested try wd40 and just look for a period of smoother idle. Looking at the charts again the manifold pressure is driving the other inputs though it could be injection. If it worked fine before and you didn't pull the manifold look for misplaced or kinked vacuum lines. It has to be simple if it was ok in the other car.
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Yeah, you’d think so… I couldn’t tell which of those parameters was following which.

There are no vacuum lines apart from the brake booster feed and I isolated that.

Throttle body has no adjustments. And the two other throttle bodies I have behave the same.

I’m going to park it for a few weeks. I’m ordering a new engine mount (a proper Lemforder one this time, the cheapie was shit out of the box…) and given the mount has to come off to get the lower manifold out I’ll do all that in one go. Have a new steel lower manifold gasket and maybe the best part of a year out of the car caused the gasket to fail in situ. Either way, back to basics.

Maybe swap the injectors over the scenic …
 
link1896

link1896

Mr Greenfield
If no egr, is there variable timing on the cams? I think the only way to drop the egr is to retard exhaust cam timing (when cold) so the intake stroke can pull exhaust gasses back in.

are all valves ok? Performed a leak down test?
 
Haakon

Haakon

has an accommodating arse
link1896 said:
If no egr, is there variable timing on the cams? I think the only way to drop the egr is to retard exhaust cam timing (when cold) so the intake stroke can pull exhaust gasses back in.

are all valves ok? Performed a leak down test?
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Yes, does have VVT on the inlet cam - it’s an all or nothing type and yes I’ve checked and swapped the solenoid. It’s off at idle and isn’t activated until close to 2000rpm. I even hot wired that to activate it at idle and it made it all a whole lot worse, so VVT is behaving as it should.

Valves should be fine, at least they were when I last ran the engine before pulling it out of the old car…
 
Haakon

Haakon

has an accommodating arse
Dales Cannon said:
Do you have a sketch of the intake system and connections?
Click to expand...
Maybe… but MAP and air temp sensor plug directly into the plastic upper manifold, there is a brake booster feed and inlet for vapour canister purge on the throttle body. That’s it. Throttle body has a duct to the air filter, which has nothing on it itself.

Injectors are in the alloy lower.
 
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