Chimaera 400 began lumbering, then went back to normal

Chimaera 400 began lumbering, then went back to normal

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NJ94Chim

Original Poster:

12 posts

11 months

Thursday 22nd August
quotequote all
Greetings all.

Yesterday, the weather was gorgeous so I took the car out to run local errands. Car is an unmodified 94 Chimaera 400.

After having been out and about, with the engine throughly warmed up, the engine began to lumber. This was the case at idle at lights/stop signs, but also when starting off from a full stop. It was like a switch had been thrown. Idle speed was still even, but sounded weak or a bit boggy. Exhaust smell was noticeably different but no smoke from the exhaust, and engine was not missing at all.

It did this for 10 minutes or so, andafter drving a bit, the problem just went away - absolutely back to its normal behavior, as if it had never happened.

Question for the group: could this have been some sort of fuel injection malfunction that affected all cylinders? Maybe the stepper got stuck wide open or totaly closed. If not the stepper, is there some other fuel inj component that could have caused this?

The car does have a tendency to hunt at idle which I attribute to needing to clean the stepper.

Any and all suggestions will be greatly appreciated.

BritishTvr450

303 posts

4 months

Thursday 22nd August
quotequote all
Rovergauge.

Could be any number of reasons from poor fuel to sticky injectors to stepper or indeed a slight vacuum leak.
If it occasionally hunts at tickover it’s time to find out what’s wrong with it as fouling the plugs won’t help either. Could even be an ignition fault as in a badly connected lead.

As tests have often shown RG is the first thing to use to narrow down the minefield of options before throwing money or ideas at it.

PabloGee

427 posts

25 months

Thursday 22nd August
quotequote all
Agreed.
Rovergauge - it's available on eBay only now I think - a specific cable that's worth every penny, and the software is free.
There are a few people on here and Facebook who know how to read it well, and once you've got your head around it, you can see what the numbers mean.
Interpreting what to do about them is another area of expertise that lives on this forum.

Clean the stepper by all means whilst you're waiting for your Rovergauge cable to arrive in the post.

NJ94Chim

Original Poster:

12 posts

11 months

Thursday 22nd August
quotequote all
Yes, I see the code repository on GitHub.

Can RG be made to run on a Mac? (I have a couple of Mac laptops, but no Windows laptop at present)

Also, it turns out that I have a Steve Heath Engineering 14CUX Fault Code Reader and cable, inherited from the fellow I bought the car from. Have not used this yet, but maybe now is the time.

Or should I go ahead and get the cable off of Ebay?

Thanks again

Belle427

9,568 posts

238 months

Friday 23rd August
quotequote all
Start with a basic inspection of the ignition system first.
A stepper clean won't hurt either if it's never been done.

sixor8

6,503 posts

273 months

Friday 23rd August
quotequote all
Are you still using the spark plug extenders? I've had a similar thing happen on 2 x TVRs with the RV8 engine. One was a loose extender, the other was it being intermittent before it failed completely (went open cct) and was then running on 7.

PabloGee

427 posts

25 months

Friday 23rd August
quotequote all
NJ94Chim said:
Yes, I see the code repository on GitHub.

Can RG be made to run on a Mac? (I have a couple of Mac laptops, but no Windows laptop at present)

Also, it turns out that I have a Steve Heath Engineering 14CUX Fault Code Reader and cable, inherited from the fellow I bought the car from. Have not used this yet, but maybe now is the time.

Or should I go ahead and get the cable off of Ebay?

Thanks again
I initially ran RG on my Mac through a virtual machine, which worked well.
I swapped to my son's PC laptop (that he no longer uses) because the wife got annoyed at me taking the house Mac laptop to work for a day so I could record the driving each way biggrin

I'm not familiar with the Steve Heath reader, but I do know that RG is more than a fault code reader. It also shows faults in a table.