SAG engine problem - please help diagnose loss of power
SAG engine problem - please help diagnose loss of power
Author
Discussion

hairyaardvark

Original Poster:

254 posts

227 months

Saturday 20th September 2008
quotequote all
Hello guys,

hopefully someone on here can diagnose what might be wrong with my Sag - two weeks into TVR ownership, aaarggh ;(

The car is a 55 Reg with ~11K on the clock. It just had it's 12K service with Sebring before I bought it a few weeks ago (from a private seller).

I was sitting in a traffic jam yesterday for about an hour. The car had been driving fine up to that point, including about 500 miles of a good mix of motorway, A and B road driving over the last week or so. I really haven't been booting it!

However, after being in the jam for about an hour (idling or going a max of 15mph in first gear), the car suddenly threw an aircon fault and the rev idle shot all over the place. I immediately turned off the aircon and fan, and had to up the revs slightly merely in order to stop the car from stalling. The idle then seemed to recover itself after a while, and settled back around 950rpm.

From that point onwards, I also seem to have lost loads of engine power. The car can still drive OK from A to B, but is so low on power that I need nearly 2K revs just to pull away from stationary in first gear. Had to drive the 20 miles or so home, and once clear of the traffic jam, I could get the car to about 85/90mph in 5th on the motorway, but it was really struggling to go any faster.

The loss of power has been accompanied by a much deeper, more blatty, woofly engine note (would almost be an improvement if it hadn't robbed the power!)

Weird! Does anyone have any clues as to what the problem might be?

Oil pressure seems normal enough (in my newbie experience that is): 7/8/9 at idle, and 47-odd psi when driving.
Oil Temp between 60 and 80 when warmed up.
Water Temp between 80 and 95.

And the car seems to settle back to idle OK, and also revs fairly freely when not in gear (obviously I haven't caned it though).

Oh, one other thing. On the way home, whilst at motorway speeds, I turned the aircon back on - and it seems to work fine! Just the engine I am worried about.

any thoughts/ideas welcome. Very worried about my new purchase frown

many thanks
David

Edited by hairyaardvark on Saturday 20th September 10:36

VARLEYHYD

2,244 posts

236 months

Saturday 20th September 2008
quotequote all
I am sure it just wants resetting on the diagnostics from what you say, literally 10 minute job by dealer/indie.

Don't worry about the air con, sometimes gets a '137 fault' when it gets really hot and re sets.

G

Pharoah

359 posts

298 months

Saturday 20th September 2008
quotequote all
Hhmmm - cant comment on the specific problem, but just to say the air con fault code used to happen on mine untill I had the sensor changed and even happened when the air con wasn't on! Hope its easily sorted, can you swing by a local dealer to check it out?

hairyaardvark

Original Poster:

254 posts

227 months

Saturday 20th September 2008
quotequote all
Thanks for your reassurance, good to hear that it isn't necessarily a serious problem.
Regarding the ECU reset ... I that something I can do myself, do you know?
On my old Subaru I could reset the ECU with a combination of full chat and simultaneously pressing the 'demist' button. Is there a TVR equivalent of this?

cheers
D

hairyaardvark

Original Poster:

254 posts

227 months

Tuesday 23rd September 2008
quotequote all
Just a quick update on this - in case anyone else ever gets the same problem : having spoken to a few experts over the phone it sounds as if the most likely problem is a collapsed cat blocking the exhaust. Will find out for certain hopefully on Thursday when I take the car into Offords in Cambridge. Fingers crossed it isn't anything even more serious!

TVR_owner

3,349 posts

220 months

Tuesday 23rd September 2008
quotequote all
hairyaardvark said:
Just a quick update on this - in case anyone else ever gets the same problem : having spoken to a few experts over the phone it sounds as if the most likely problem is a collapsed cat blocking the exhaust. Will find out for certain hopefully on Thursday when I take the car into Offords in Cambridge. Fingers crossed it isn't anything even more serious!
Unusual I must say and I would personally doubt if this is the case.

If it is however I would be very careful driving the car between now and then. There is a very real possibility that a collapsed cat or one that is breaking up, can be ingested udner high vacuum condistions and an ingested cat will be very serious..

KillerJim

972 posts

232 months

Tuesday 23rd September 2008
quotequote all
The throttle pot's may need balanced as well, I had the screw that controls the balance come lose on my Sag and the car started to run very rich.. the sound certainly changed to something I would decribe as 'woolfy' - its like its breathing deeper or something, and power was extremely screwed..

J

hairyaardvark

Original Poster:

254 posts

227 months

Tuesday 23rd September 2008
quotequote all
Thanks Jim - is that something I can check myself? I'm still planning to take her into the dealership on Thursday but it would be good if i could spot something worth tightening before I attempt the trip ....

cheers

s6boy

1,854 posts

254 months

Tuesday 23rd September 2008
quotequote all
Thought I'd pop over quickly from the proper car forum wink If the car has been serviced recently at Sebring I'd highly recommend taking it back there to have the diagnostics checked out as that has got to be the most logical start point and Matt the spanner man is very good.
Collapsed cat I would be very surprised at and it sounds like the diagnosis was made over the phone? Sorry to say, but if that was a dealer telling me that without looking at the car I'd tend to go elsewhere. All IMO.

tuscan s

202 posts

253 months

Tuesday 23rd September 2008
quotequote all
s6boy said:
Thought I'd pop over quickly from the proper car forum wink If the car has been serviced recently at Sebring I'd highly recommend taking it back there to have the diagnostics checked out as that has got to be the most logical start point and Matt the spanner man is very good.
Collapsed cat I would be very surprised at and it sounds like the diagnosis was made over the phone? Sorry to say, but if that was a dealer telling me that without looking at the car I'd tend to go elsewhere. All IMO.
I would give matt a ring as the people you are takeing it to will not have a clue, took my car there a little while ago and they said it was a kancked cat, took it to the experts in north london (barnet way) all it was, was throttle bodies came loose... You have been warned..

Zippee

14,125 posts

263 months

Tuesday 23rd September 2008
quotequote all
tuscan s said:
s6boy said:
Thought I'd pop over quickly from the proper car forum wink If the car has been serviced recently at Sebring I'd highly recommend taking it back there to have the diagnostics checked out as that has got to be the most logical start point and Matt the spanner man is very good.
Collapsed cat I would be very surprised at and it sounds like the diagnosis was made over the phone? Sorry to say, but if that was a dealer telling me that without looking at the car I'd tend to go elsewhere. All IMO.
I would give matt a ring as the people you are takeing it to will not have a clue, took my car there a little while ago and they said it was a kancked cat, took it to the experts in north london (barnet way) all it was, was throttle bodies came loose... You have been warned..
Give Matt a call!!! See what he says and if in doubt get it recovered over there!!!

hairyaardvark

Original Poster:

254 posts

227 months

Wednesday 24th September 2008
quotequote all
Thanks for all the advice guys, I will certainly give Matt a call today to see what he thinks. Problem is - Sebring is an awful long way to drive with a potentially knackered car. So I will still take it into Offords tomorrow. If they can't help I'll have to see if I can get the car up to Sebring after all, somehow.

Just on other thing to note - no one has actually made any firm diagnosis over the phone, just a 'most likely' guess, based on the symptoms I described.

philcerb

102 posts

236 months

Wednesday 24th September 2008
quotequote all
Hello David

A Friend of mine uses Matt on him Chimaera and he said that he is brilliant. But also some people say the Offords are also good. I live 5 miles away from Offord but i use Guglielmi at Daventry because he is fantastic

tuscan s

202 posts

253 months

Wednesday 24th September 2008
quotequote all
philcerb said:
Hello David

A Friend of mine uses Matt on him Chimaera and he said that he is brilliant. But also some people say the Offords are also good. I live 5 miles away from Offord but i use Guglielmi at Daventry because he is fantastic
Could i have a bit more info of the people you use in daventry please.........

tail slide

2,169 posts

276 months

Wednesday 24th September 2008
quotequote all
tuscan s said:
philcerb said:
Hello David

A Friend of mine uses Matt on him Chimaera and he said that he is brilliant. But also some people say the Offords are also good. I live 5 miles away from Offord but i use Guglielmi at Daventry because he is fantastic
Could i have a bit more info of the people you use in daventry please.........
Seconded. Steve Guglielmi & team have years of experience of TVR's inc. engine builds, & race preparation. Transformed my GinettaG33 into TVR-engined hillclimb winner biggrin

http://www.guglielmimotorsport.co.uk

hairyaardvark

Original Poster:

254 posts

227 months

Thursday 25th September 2008
quotequote all
Just spoke to the garage and I'm relieved to report that they have identified the problem. Apparently at some point I've had some water ingress into some of the ignition wiring (he mentioned exactly what, but I forget), which in turn recently stopped 2 cylinders from firing at all! It is strange that the problem only manifested itself after sitting in a traffic jam for ages - but thats cars for you I suppose.

He also mentioned a perished oil seal (unrelated to this problem apparently) which is leaking oil and really ought to have been replaced at the recent 12K service. Sounded very surprised it wasn't done.

Anyhow they seemed to have a good level of confidence that all would be well again very shortly. ;0)

KillerJim

972 posts

232 months

Thursday 25th September 2008
quotequote all
hairyaardvark said:
He also mentioned a perished oil seal (unrelated to this problem apparently) which is leaking oil and really ought to have been replaced at the recent 12K service. Sounded very surprised it wasn't done.
Not good in that respect..

I think everyone have niggles with their T350's and Sagaris'..

My 6 month report happens to be be a misaligned speedo sensor, throttle balance screw came out and the exhaust bracket broke (and rattled)

In all cost me £150 biggrin

J

hairyaardvark

Original Poster:

254 posts

227 months

Tuesday 7th October 2008
quotequote all
Just in case this ever happens to anyone else .... thought I'd complete the thread with the final diagnosis.

I now have the car back and she drives beautifully (aircon is still a damp squib but I guess 'they all do that sir' ;0) )

The problem was definitely caused by corroded ignition wiring which finally gave up the ghost whilst i was in that traffic jam a few weeks ago, and was originally caused by water ingress into the wiring loom which looked like it had been badly wrapped originally, at the factory.

Was very pleased with Offords TVR service overall as well, they seem like a competent bunch and didn't either assume too much mechanical knowledge on my part, or come over as condescending.

The £571 repair bill was a little bitter to swallow two weeks in my TVR ownership experience, but then again, I went into this with my eyes open.

The drive home alone made it worth it