vectra sri140 koltec egi not going above 3k rpm

[optimus]

hi,
I recently purchased an X reg sri140 vectra (x20xev engine code) with factory fit LPG system. It looks like it is the koltec EGI system with the separate distributor after the vaporizer.



The system will run but will switch back to petrol at about 3k rpm in any gear. when switching back the engine management light illuminates for about 30 secs then goes out.
I checked the codes with opcom and they were as follows
P1690 - (2) - telltale checklight low voltage - present -- the management light works so why the code?
P0201 - (1) - Injector valve 1 voltage high - present -- this i'm not sure about
note: these codes come up as - present when in LPG mode and - not present when in petrol.

I erased the codes and kept the opcom running and switched from petrol to LPG as soon as you switch over the codes appear, this is while idling on the drive.

I anybody could help with these issues or direct me to a service agent who knows about these system in the Shropshire area I would be very grateful

[pjpj]

See this thread and its associates:-

http://www.lpgforum.co.uk/viewtopic.php?f=28&t=9984

It is possibly the emulator that is faulty or it could be a wiring/ connection issue at or around the emulator.

[optimus]

I currently have the interior in pieces as in process of fitting climate control.

I have looked at the connections on the LPG ecu and they seemed okay, good stiff contact no sign of corrosion. I took all the relays out and they were all clean on the contacts so i swapped them all round but will have to wait till later in the week to see if it's done anything. The relays are all black and have the same details on them.
Below is a couple photo's of the wiring and ecu

[pjpj]

Check the continuity of the wiring between the emulator you have photo'd and the relays it connects to.

It's probably worthwhile trying to contact the other poster by PM to see if he has got anywhere with his. This code 1690 issue is a puzzler.

[optimus]

meant to mention I tried the diagnostics method and all i got was a solid red light for about 2 secs then nothing, I left it for about 30 secs after that to see if anything came up and nothing did

[daveylitz]

parts are the bloody same to! lol

[optimus]

Took car to a specialist in the cheshire area. when i got it back he said the system seamed to be okay and pretty clean he did notice some issues while he was running his tests though

1 - found a split in the underside of the MAF to TB pipe work. Has taped it up and that seams to let the system go over 3k rpm without reverting back to petrol
2 - intake manifold is leaking air abit around the mating face to the block so possibly gasket on it's last legs, know to crumble or go solid over time
3 - EGR valve possibly playing up so suggests blanking off
4 - He had to adjust the throttle lever as he says it's a bit stiff and screw was to far out or something
5 - check out where the LPG lines go into the manifold, know for working loose

Apparently the system are run by the main ecu or something and the codes don't always appear, something to do with age of car possibly. will report back later on when fixed some of the leaks and see how the car runs

[daveylitz]

the lpg ecu piggy backs the petrol ecu, my next job is to trace the connections and check them

[daveylitz]

have you getting any further yet?

[optimus]

been a while since i've been on. The car did start running better after i replaced the air intake pipe which I had a massive split on the underside. Then recently It started playing up on lpg again. While recently doing some changes to the car I had the inlet manifold out and found the injector unit on cylinder one was a bit loose with a bit broken that holds it onto a nipple with a circlip. The egi system injectors are like a large round diaphragm by the looks of it and are passive. I managed to locate a company that sold the injectors and found them to be rather cheap at about £10 compared to the cost of the other types of injectors. I've replaced the damaged unit earlier and will be keeping an eye on it's behavior over the week.

[optimus]

Have had an lpg specialist a friend knew have a look at the system. After a few hours mucking about he came to the conclusion that it is likely the lpg ecu is buggered as the gas is coming through but not being regulated properly, also thought the motor in the top of the distributor could be a problem.

His recommendations were either locate a known working ecu and distributor motor 2nd hand or find a different front end lpg system and fit it to the car. If fitting a different system he has recommended a multipoint system

[rossko]

Seems a bit rash, what you have is a multipoint system

I would look into cleaning out the distrubutor and AFCO valve before condemning it, there is an art to this where I will defer to pjpj to eloborate

[pjpj]

I'm confused now.

This was your original fault from the first post.

P1690 - (2) - telltale checklight low voltage - present -- the management light works so why the code?
P0201 - (1) - Injector valve 1 voltage high - present -- this i'm not sure about

Is this no longer a problem?

If you are having poor running at slow speeds it is likely the distributor needs cleaning.

A new stepper motor can be obtained from autogas2000 as well as a rebuild kit for the distributor and vaporiser if you need.

I will PM you.

[optimus]

we had the system pretty much stripped, there was gas coming through to the distributor. we spent a good couple hours working on the thing, he even turned the pressure up on the vaporiser. Took the bottom of the distributor off seeing if the filter needed cleaning but found there was none, had a diaphragm with a spring under neath. He tried a couple of the motor things ( AFCO valve ? ) he had lying around and the system wasn't having it, just cut out, wouldn't even idle.

The EGI system isn't multipoint as it's not controlled on each cyclinder, it's more akin to the old single point injection system as I see it. The disc units on the end of the lines from the distributor are there to prevent any blow back so you could actually do away with them and connect the lines directly to the manifold

@pjpj - the codes mentioned are still present and I would be interested in any theory's as to what is causing them. One theory is because of the sudden voltage surge when switching that may be the cause but is uncertain. Also as for original fault it was the fact of not going above 3k rpm's. That fault has now worsened to not getting above 2.5k rpm's, when trying to do so it would seam as if the engine is being choked/starved then suddenly jump back to petrol.

[rossko]

Doesn't sound like the distributor has been cleaned properly, you usually need to make a special tool to do it. But it doesn't sound like anyones changed the liquid filter yet? Clagged, it would limit throughput.

The diaphragm gubbins is 'DFCO', not AFCO as I misremembered

I can assure you the EGI system is correctly termed multipoint, the gas being introduced to the engine at multiple points. When in working order it works fine, there is nothing to be gained performance wise by fitting an injection system (note that all injectors on a 4-cyl engine open for the same duration and there is no individual cylinder metering). It's your car of course, you're free to bin it!

I wouldn't worry too much about the fault codes, I've come to the conclusion that early EGI throw the injector fault when gas is selected and inhibit the fault light, so those would marry up.

[pjpj]

just cut out, wouldn't even idle.

So is the car running on gas at all now?

That fault has now worsened to not getting above 2.5k rpm's, when trying to do so it would seam as if the engine is being choked/starved then suddenly jump back to petrol.

Or is it now doing this.

Whichever way, you have a blockage. Injectors blocked (You can blow down each one in turn when disconnected at the distributor.), Stepper Motor faulty, vaporiser gummed up, wet filter gummed up, solenoid valve (Front and/ or back) gummed up, damaged pipe or ECU not controling the stepper motor correctly.

The emulator returns an artificial signal for each petrol injector, if you measure the outputs from the emulator feeding back to the petrol ECU you will find one, probably cylinder1 isn't doing this. I can't see why this would be done by design, what would be the point of the emulator at all?

[optimus]

when testing the other stepper motors it was cutting out, with the original it will idle and goes upto about 2k rpm in 1st or 2nd gear and it would loose all power like it was being choked/starved I haven't pushed it much to see if it goes back to petrol in these gears, 3rd gear onwards it just cut's out back to petrol between 2k - 2.5k rpm. If there was a blockage i would think that there would be no gas coming through or very little, that aside I will be double checking things.

PjPj - you seam to have some of the similar ideas with the technician with regards to ecu/emulator faults. The codes do seam to be an inherent fault with these systems I believe another member had similar faults and I have heard of others through other forums. This could mean that as the systems get older the emulator develops a common fault, who knows. All I can tell is that the codes come back even when you manually switch over and not just the system switching back automatically

[rossko]

If there was a blockage i would think that there would be no gas coming through or very little

What symptoms might you expect if insufficient gas could get through?

[pjpj]

when testing the other stepper motors it was cutting out,

If the stepper motors were from a Volvo or some other factory fit system, the systems are the same but the stepper motors work differently. This is besides the fact that anything lying around in a workshop is unlikely to be a worker. It seems the Volvo stepper motors were much less reliable.

Start at the beginning of the fuel feed, the tank solenoid valve, and work your way forward. Strip and clean or replace the solenoid and valve.

I assume you have no fault codes on the LPG ECU?

[optimus]

sorry I haven't gotten back sooner, haven't gotten to the route of the problem unfortunately. Haven't got the software or leads to interface with the ecu and no codes through the earth method. Another possibility that cropped up was that the battery in the ecu could of died and the systems lost all settings.

Have bought a new front end system to replace it, thanks for all your help thus far guys

Merry Xmas and a Happy New Year