Help.............4th/5th gear
28 October 2003, 09:50 PM
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Hello guys. Have just joined the scooby gang and i think ive hit the 1st problem already. The car is a 97 R and has 50000miles. The car has been chipped (superchipped) has a DV and cat-back exhaust.
I took it straight to well lane to get it on the rollers and get it all checked out, it made 257bhp and peaked up @ 15psi. Fuelling etc was checked and everything was fine. However today, the car was valeted and the engine bay steamed, everything seemed fine.
PROBLEM......
Was on a motorway journey and planted the accelerator in 5th @ approx 70mph, got to around 75-80 and just stopped, it was the feeling you get when you hit the engine limiter, I would imagine this to be a fuel cut off. Again i accelerated in 4th from around 60mph, same happened. However if i squeeze the accelerator gently in 4th or 5th the car will keep pulling and i dont have this problem, but its at snail pace. There is no problem in 1st 2nd or 3rd, will hit red line in each of these gears. This seems to me very very weird, whats going on??
Would the steam cleaning of the engine bay affected the boost, ecu? but then again 1st 2nd and 3rd, the boost seems fine and pulls like it normally does.
It only happened twice as the missus was in my ear telling me not to chance it, and every time i went to accelerate, she went off her head. You know what there like. Winge winge winge.
What's the problem??
Cheers for your time.
[Edited by Loon - 10/28/2003 9:51:46 PM]
I took it straight to well lane to get it on the rollers and get it all checked out, it made 257bhp and peaked up @ 15psi. Fuelling etc was checked and everything was fine. However today, the car was valeted and the engine bay steamed, everything seemed fine.
PROBLEM......
Was on a motorway journey and planted the accelerator in 5th @ approx 70mph, got to around 75-80 and just stopped, it was the feeling you get when you hit the engine limiter, I would imagine this to be a fuel cut off. Again i accelerated in 4th from around 60mph, same happened. However if i squeeze the accelerator gently in 4th or 5th the car will keep pulling and i dont have this problem, but its at snail pace. There is no problem in 1st 2nd or 3rd, will hit red line in each of these gears. This seems to me very very weird, whats going on??
Would the steam cleaning of the engine bay affected the boost, ecu? but then again 1st 2nd and 3rd, the boost seems fine and pulls like it normally does.
It only happened twice as the missus was in my ear telling me not to chance it, and every time i went to accelerate, she went off her head. You know what there like. Winge winge winge.
What's the problem??
Cheers for your time.
[Edited by Loon - 10/28/2003 9:51:46 PM]
29 October 2003, 09:30 AM
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Does sound like over boost to me, the symptoms all fit. What fuel do you run? Maybe worth trying a lesser "ron" fuel, might help matters. Could try running on BP ultimate instead of Optimax.
It may help you never know. But simple thing to try first before having any other alterations done.
It may help you never know. But simple thing to try first before having any other alterations done.
29 October 2003, 10:11 AM
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Might be worth checking boost control solenoid. If it's never been cleaned, after 50,000 miles, might well be oily. Although strange nothing showed up at Well Lane. I think the steam clean is a red herring. Although I don't think Scoobs like being steam cleaned...
It certainly sounds boost related. The reason you're not noticing it in lower gears is due to the load on the engine not being as high. That's why when you instal a manual boost controller, you set it up based on the higher gears, otherwise the chances of hitting fuel cut are substantially higher. Actually, that's a point. Do you know if yours has a manual boost controller...?
Regards,
Ade.
It certainly sounds boost related. The reason you're not noticing it in lower gears is due to the load on the engine not being as high. That's why when you instal a manual boost controller, you set it up based on the higher gears, otherwise the chances of hitting fuel cut are substantially higher. Actually, that's a point. Do you know if yours has a manual boost controller...?
Regards,
Ade.
29 October 2003, 12:49 PM
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All i know that the car was superchipped before i bought it and when it was on the rollers @ well lane peak boost was reaching 14psi, he told me it should be peaking at 15psi and he adjusted something in the engine bay. (it was in front of the shock strut directly in front of the driver on the right side, i think he just turned the screwthread with a screwdriver and thats how the boost was upped. 15psi only upped bhp by around 3-4hp, from what 14psi was recording.
When does the ECU sense overboost? At what psi reading??
The thing is, i went out to test the car this morning, and ragged it up through the gears to silly speed in 5th. Everything was fine, responded how it should do and picked up well.
Would using optimax, and a cold damp night up the psi figure to the overboost point?? Ive got a feeling the boost was set originally at 14psi, using normal unleaded. Well lane have upped the figure to 15psi and by using optimax and a cold damp night, the pressure may have upped more.
Does this sound silly, or is this making sense? Im not the best technically minded but thats what my brains telling me at the moment.
When does the ECU sense overboost? At what psi reading??
The thing is, i went out to test the car this morning, and ragged it up through the gears to silly speed in 5th. Everything was fine, responded how it should do and picked up well.
Would using optimax, and a cold damp night up the psi figure to the overboost point?? Ive got a feeling the boost was set originally at 14psi, using normal unleaded. Well lane have upped the figure to 15psi and by using optimax and a cold damp night, the pressure may have upped more.
Does this sound silly, or is this making sense? Im not the best technically minded but thats what my brains telling me at the moment.
29 October 2003, 01:19 PM
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Sounds like it overboosted and hit a limiter but the car has been chipped, so would expect the boost limit to have been raised.
If it's just a bleed valve that has been fitted, then sounds like because the weather was colder, you will have overboosted and hit the limiter.
Bear in mind that you don't get the same cold air on a rolling road as you would out on the open road, so with 14psi being shown on the rollers i would expect the boost to be slightly higher out on the road.
With 1st, 2nd and 3rd gear, the car probably didnn't have enough time in the overboost limit for the ECU to act upon it. Don't know about the earlier cars but the phase II have their limit at 18psi, but has to see that for 2 seconds before the cut comes in.
Alan
If it's just a bleed valve that has been fitted, then sounds like because the weather was colder, you will have overboosted and hit the limiter.
Bear in mind that you don't get the same cold air on a rolling road as you would out on the open road, so with 14psi being shown on the rollers i would expect the boost to be slightly higher out on the road.
With 1st, 2nd and 3rd gear, the car probably didnn't have enough time in the overboost limit for the ECU to act upon it. Don't know about the earlier cars but the phase II have their limit at 18psi, but has to see that for 2 seconds before the cut comes in.
Alan
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