New Owner - Help/advice please

[SirSagalot]

I am the new and proud owner of a 99 4.0 Chimaera. All standard until I stuck Clive's Y piece on, put ACT coolant hoses on, changed the Plenum elbow and the ACT Trumpets (although my mate did that). All was good until the last weekend when the engine started to surge at idle and cut out going round a corner. So, did some research and spoke to my mechanic buddy and changed the stepper motor. All was great, took it for a run and then just as I got home it cut out. It restarts fine but won't hold the idle. I've had a look on the forum but couldn't find anything that leapt out.

Any advice would be really appreciated as I have already taken too much of my mates time. Thanks.

[SILICONEKIDOBHP]

SirSagalot said:

I am the new and proud owner of a 99 4.0 Chimaera. All standard until I stuck Clive's Y piece on, put ACT coolant hoses on, changed the Plenum elbow and the ACT Trumpets (although my mate did that). All was good until the last weekend when the engine started to surge at idle and cut out going round a corner. So, did some research and spoke to my mechanic buddy and changed the stepper motor. All was great, took it for a run and then just as I got home it cut out. It restarts fine but won't hold the idle. I've had a look on the forum but couldn't find anything that leapt out.

Any advice would be really appreciated as I have already taken too much of my mates time. Thanks.

Did he fit an after market stepper motor ? You might of been better off cleaning the old one .

[SirSagalot]

I got a new one from Clever Trevor and fitted it. Given the cost of it I think it's am genuine part. Thanks

[Chuffmeister]

Check for air leaks

[SirSagalot]

Thanks. Is there a certain way of doing that?

[Chuffmeister]

Some say use Damp Start, spraying it near the seals/ joins and then listening for the revs rising. Alternatively, check for air leaks around the stuff you've just re-fitted; ie. plenum, trumpet base and induction hoses.

[shake n bake]

Proof in the pudding that after market parts aren't worth the bother.
Put back one peice at a time and rule out your potential problems, stepper seems likely but who knows, only time and a bit of diagnosis will show for sure.

[Chuffmeister]

shake n bake said:

Proof in the pudding that after market parts aren't worth the bother.
Put back one peice at a time and rule out your potential problems, stepper seems likely but who knows, only time and a bit of diagnosis will show for sure.

Forsake thou user of OEM and aftermarket parts. Repent... Repent!!!

[SirSagalot]

Thanks - I'll try that. The Stepper Motor was an original part and cost around £50. Appreciate all the advice.

[QBee]

SirSagalot said:

I am the new and proud owner of a 99 4.0 Chimaera. All standard until I stuck Clive's Y piece on, put ACT coolant hoses on, changed the Plenum elbow and the ACT Trumpets (although my mate did that). All was good until the last weekend when the engine started to surge at idle and cut out going round a corner. So, did some research and spoke to my mechanic buddy and changed the stepper motor. All was great, took it for a run and then just as I got home it cut out. It restarts fine but won't hold the idle. I've had a look on the forum but couldn't find anything that leapt out.

Any advice would be really appreciated as I have already taken too much of my mates time. Thanks.

I had this after fitting a Clive Y. So did another Chim owner. Mine turned out to be the stepper motor, though we re-adjusted everything first....tried disconnecting the stepper when we had a good idle, reset the throttle pot voltages, checked for air leaks, checked the AFM voltages, unplugged the ECU etc.

What was happening was that the car was fine cold, but when hot would not hold an idle of any sort.

It seems that the Clive Y revealed some sort of temperature sensitivity in my stepper. No idea what or how. Cleaning it didn't cure it. Swapping it for an old but original stepper solved it.

[QBee]

PS that was 12 months and 13000 miles ago. Never had any issues since.

[ClassiChimi]

Lucky bugger, lol. It's probably the mileage you do that keeps the stepper in good order Qbee. Hi mate.

[QBee]

It was a strange one. Mark Adams remapped the car, as I had had a lot changed, but didn't solve the stalling. I tried all sorts of stuff, failed, so as a last resort rang Rob (V8 Developments) for advice and took it to him. He spent an hour resetting and checking everything with a multimeter, couldn't fix it, cleaned the stepper etc, checked again for leaks, then said to himself "it MUST be the stepper". I suggested he rummage for an old one to eliminate it, he found and fitted it, and.....problem solved.

[ClassiChimi]

A blessing Anthony, that's my issue but I keep cleaning it then it plays up and on like that. It's time I gave in and just got another one.

[SILICONEKIDOBHP]

NickOrangeTVR is using a stepper from a BMW.

[Duke Thrust]

Have you checked your base idle speed?

[SirSagalot]

Thanks again all. I will try all the above and let you know if the problem is solved. All a big learning curve for me so appreciate all the advice.

[SirSagalot]

Well Clever Trevor really is Clever. After spending £65 (checked the invoice) on a new stepper motor that caused me to post on the forum, I have cleaned and put the old one back and she seems to be ok.. The revs idle high for a few secs when engaging the clutch and then drop back to around 900. A much better situation than I was in 24 hours ago. So I am going see how things go for a while. Appreciate all the input and hopefully I can one day assist others (albeit unlikely).

[QBee]

Mine does that from time to time. Something to do with the tide tables I think..

[kevd]

Did you Change the tune resistor after fitting the decat y piece?
As I believe this can cause idling problems