Sag Throttle issue

Author
Discussion

phoenixz

Original Poster:

439 posts

165 months

Tuesday 16th May 2017
quotequote all
Having trouble with my throttle.

Symptoms: intermittently, on idle, the revs drop when touching the accelerator (almost to the point of stalling). this will happen randomly at any temperature, any speed, inclines, declines, flat etc. as long as the car is idling it can happen.
it is intermittent, which makes it hard to pin down the problem and also makes traffic / slow driving very difficult.

Tried so far: throttle pot re-aligned, full 12k service, switched ECU, checked linkage / connections.

would welcome any suggestions.

Many thanks,
Phoenixz

Bev400

23 posts

95 months

Tuesday 16th May 2017
quotequote all
Have exactly the same issueon my Sag. Jason believes it will be the wiring loom so I'm currently waiting for one on order.

Bev

ShiDevil

2,292 posts

173 months

Tuesday 16th May 2017
quotequote all
Plugs, Leads or Coil Pack?

KillerJim

968 posts

202 months

Wednesday 17th May 2017
quotequote all
Sounds similar to what I had, basically at idle putting down the pedal in the course of normally moving off caused a drop in rev's before she would push on through (iirc it was a little rough until she got out of the "dead" zone in RPM terms)

For me it was the balancing of the throttle pots that fixed it..

phoenixz

Original Poster:

439 posts

165 months

Wednesday 17th May 2017
quotequote all
Bev - please let me know whether the wiring loom sorts it. really hope that isn't the issue.

ShiDevil - plugs, leads and coilpack were replaced last year during an engine rebuild so it shouldn't be that.

KillerJim - I was informed after the 12k service that the throttle pots were re-aligned, but I will ask them again to make sure.

phoenixz

Original Poster:

439 posts

165 months

Wednesday 17th May 2017
quotequote all
Thanks all for the suggestions though

Incognegro

1,560 posts

132 months

Wednesday 17th May 2017
quotequote all
Thermal pads?

phoenixz

Original Poster:

439 posts

165 months

Thursday 19th October 2017
quotequote all
We finally have a resolution!!!

Thank you for the responses and suggestions, I am making sure to update this posting for anyone else that suffers that same problem.

The root cause was due to wear in the throttle bodies. Cylinders 4,5&6 opened first (due to wear) whilst cylinders 1,2&3 were still closed causing the rev to drop. It was discovered/confirmed as it shows as zero throttle movement on the laptop.

The throttles are being rebuilt as we speak and then modified to include roller bearings on the throttle spindles (also inlet heat barrier gaskets, but that isn't directly related).

Hope this helps others and maybe saves them from replacing the wiring loom (a route that I did not go down, but was going to be the next step)

Thanks again,

Andy_mr2sc

1,223 posts

175 months

Thursday 19th October 2017
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Is your car at HHC per chance?

mk1fan

10,507 posts

224 months

Thursday 19th October 2017
quotequote all
If 'Andy' is doing your TBs can I suggest you get the spindles knife edged too.

Nice job Andy does.

Andy_mr2sc

1,223 posts

175 months

Thursday 19th October 2017
quotequote all
It's a bit late if they're the ones I think they are as I put them in the post this morning!

Thank you for the positive comments though!

mk1fan

10,507 posts

224 months

Thursday 19th October 2017
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The work is good. Customer service is appalling though biglaugh

phoenixz

Original Poster:

439 posts

165 months

Thursday 19th October 2017
quotequote all
The knife edged option was not offered. Does it make a noticeable difference?

tvrtuscans

1,009 posts

210 months

Saturday 21st October 2017
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I had same problem - tho symptom was a tad more dramatic - throttle jammed open as I started it in the garage! Jason replaced throttle bodies with associated upgrade too. Usual excellent service from STR8SIX - needed the car for the 70th weekend and job done as urgent job.

mk1fan

10,507 posts

224 months

Saturday 21st October 2017
quotequote all
phoenixz said:
The knife edged option was not offered. Does it make a noticeable difference?
About 40-50bhp. laugh



Just the sprinkles on the cream.