Vauxhall XE on TBs won't rev

[Galveston]

Hello,

I've been helping a friend fit a replacement Vauxhall XE to his Westfield. We got it all back together today but while it starts easily and idles quite sweetly any attempt to open the throttle has it coughing, spluttering and cutting out. The car's running an Omex 600 ECU with Jenvey TBs.

The car hasn't run for about three years (since the old engine failed). The old engine was standard except for a set of fast road cams. The new engine is completely standard. We'd presumed that the existing map would be okay in the short-term, at least to get the car running, but perhaps not?

Any ideas what we've over-looked?

Thanks, Rob.

[GreenV8S]

Any sensor. Assuming you have the Omex software you should be able to see the raw sensor values and give them a sanity check.

You don't say what you're using for load but pay particular attention to that.

[OldGermanHeaps]

They were quite hard on ht components i'd start with plugs, leads and a dizzy cap, modded ones need tbe rocker cover ccv plate opened up a bit, other than that, stale fuel, gummed up filter, stuck fpr, crap in the wee filters in the injectors? How did it run before it was layed up?
IIRC early and late crank sensors differed also. I cant remember if the teeth on the pickup wheel were slightly different or not, there wefe some ecu differences between cat and non cat models.

Edited by OldGermanHeaps on Saturday 2nd December 21:45

[Galveston]

Thanks chaps for the speedy replies.

My first thought was sensors, and we'll explore those a bit. I think it just uses a TPS for load, but I'm not massively au fait with these systems so not sure what the alternatives might be.

Yep, definitely some logic in exploring the basics first. As far as I'm aware it ran well enough previously.

[Galveston]

Interesting about the crank sensor... the 'new' engine is later than the one it's replaced but the old crank sensor has been reused.

[OldGermanHeaps]

There may be a diiferent number of teeth on the pickup wheel, i can't remember exactly been nearly a couple of decades since messing around with these, there was deffo a difference 8v to 16v and there were a few electrical differences between the various xe variants as well. If you disturbed the crank pickup they were also fussy about the sensor to pickup distance.
I'd love another mk2 valver but i think the reality compared to todays metal would probablg tarnish some fun memories.

[GreenV8S]

Galveston said:

not sure what the alternatives might be

The two common options are alpha-N (via throttle position sensor) and MAP (via manifold absolute pressure sensor).

The fact it idles suggests you probably have a good signal from the crank / cam sensors. Is the fuel pressure right?

You don't say whether you have the Omex software running, but if so you should watch the live display and see whether it's running on the right part of the map at idle and as you open the throttle. If you don't have it yet, I'd suggest getting hold of that should be a priority.

[DVandrews]

Check the throttle position sensor, if the ECU doesn’t see the wider throttle opening then it will be under-fuelled, seen this a number of times.

Dave

[Galveston]

Thanks chaps, that's given us a few avenues to explore.

(We're yet to hook it up to a laptop).