Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Kev93]

Hey, guys, I've got lotsa questions ... do I put them all in one thread?  

Anyway, cruising at 65 to 70 MPH with CC on ... I get a lot of "surging", sometimes even to the point I have to turn the CC off and just use the foot (which is more fun, but that's not *always* the point).  CC realizes it's down a MPH or two, hits it, turbo boosts up to 5-7 PSI or so, and we're way over the threshold before the CC can even do anything about it.

Is there anything that can be done about this?

[rcdraco]

Is the exhaust system in good shape?  Mine will cruise fine above 45 up any sort of hill, the second it dies down the boost comes in right up to about 9 psi, then just smooths off the throttle to hold the speed.

It's perfectly normal for it to go into boost to pick up some power, but if it's shooting right over the cruise, it sounds like there might be some problem with it controlling boost pressure.

[Rocketman]

Kev, are you modified? Once I went with a boost controller, and after even more mods the CC becomes a little erratic. I don't think the computer can respond fast enough to the increase in acceleration

[Kev93]

I'm not sure about the exhaust system ... pretty sure it's stock, and my mechanic who helped me get it "road-worthy" made no comment on it, nor did he do any work.  Given that it's fairly quiet *outside* at idle, I *think* it's OK, but I'll have to get back to ya on that one --- hopefully I can find someplace nice to get under it (no garage at home, yet).

As for modded, I don't *think* I am.  I don't see any evidence, nothing was mentioned at time of sale,  mechanic didn't say anything, etc.  However, Rocketman, your description seems to be "spot on" with the effect I note.  

I will add that it's not so noticeable if the load is easy, but against a headwind, for example, it can get downright annoying, as I said.

How would I know if the turbo is modded?  Boost gauge never goes above about 11, so I think that'd indicate a stock turbo?

Thanks, gents!

[Rocketman]

Well the exhaust will have little to nothing to do with it unless its custom 2.25" or 2.5" resulting in a fast spooling turbo.

Check under the hood for a boost controller on the wastegate line. Stock boost should read 7-9lbs if you are seeing 11psi you might have a boost controller installed.

Otherwise it might just be a "downside" of having a turbo  

[Gostlrs]

I havent had that kind of issues on any of my turbo cars with the cruise.

Look into the vacuum lines. It could be a sign of the controller starting to go out. No way the car surging is "normal"

[Rocketman]

Jamie - controller?

[Gostlrs]

not boost...

the cruise control module

[Rocketman]

Why vacuum lines though? The capri has electronic servo for cruise control

[Gostlrs]

Vacuum lines in general. if one is leaking it can cause various things to include surges. or his cruise controller is acting a fool causing the erratic reactions.

[Rocketman]

I'm going to go ahead and say no, probably not to the vacuum lines. Unless it was his wastegate line, even then he'd notice overboosting during normal hard driving. These cars don't like to run when there's any sort of vacuum issue

[rcdraco]

Could also be a problem with the air bypass valve's vacuum, which logically could cause these problems, but I think you'd have noticable driving issues if that was the case.

[Kev93]

Well, thanks for all the posts!  I'll try and investigate some of this stuff if I can find garage space (I'm hoping to build one this summer, but wifey prefers a new kitchen instead ... budget may not permit both - and you know what they say, "if mama ain't happy"...) or when weather permits (it has been better than last winter so far, hasn't it?)

I'll have to eat a little crow on my purported boost up there.  I've gone out and hit it hard as I can a couple times, and the needle is *touching* 10, but on the low rather than high side, so 9.x PSI it is, not 11.  I'll plead that it's the excitement, adrenaline and general "newness" of the experience that had me not really notice which side of "about 10 PSI" we were on.

I have noticed it's only during "load" that I'm having this issue ... headwinds the other day, and today, trying it at 55 MPH on small hills.

I've got a big laundry list of stuff to do with this car, and I'll hope to someday address this one.  Meantime, I've got several niggling "comfort" issues that need to be solved ... (see the above "mama" comment    )