avcwo

Here is what I need help with. My CTTC hesitates under boost conditions ONLY. Runs great otherwise. It just started happpening. The previous time I drove it, it was PERFECT...in fact better than ever.. An hour later...Bang! my problems arise..

I need info on a few things;

1. Does it sound like a microfueler? If so WHERE can I get it repaired, or better, replaced/upgraded? I talked to Scott Rawlings at Callaway Engineering and he said they no longer service them. He directed me to Bill Woods, whom I emailed to get no response. Like I said, it was working fine...then my issues happened.

BEFORE this occurance, I had been refurbishing the car from inside out. I have replaced:
1. BOTH turbos with updated internals, but kept the original housings. Turboworks (Reed Patridge) did the work modifying the external parts to fit new Americam made internals. They were set up to be as close to original as possible in output to avoid the need to remap.
2. Fuel pump (from Callaway), fuel filter (shielded properly), all fuel lines (including to Rams Horn), fuel pressure regulator, ALL injectors (OEM type for cylinders, correct P/N Bosch injectors for rams horn), plus wires, plugs and distributor.
3. Turbo oil and coolant lines.
My additional questions are;
1. What should fuel pressure be at idle? WOT?
2. How long should the system hold pressure with the Callaway high pressure fuel pump. With BOTH the old correct pump and the newly installed one one, line pressure dropped to 0 after about 7 minutes. Other CTTC owners say that is normal..is it??
3. Any other ideas as to why I'm getting hesitation?

Thanks
avcwo

SurfnSun

How much gas in your tank? The torque of the b2k will push the gas away from the pickup when you are a 1/4 tank or less causing the car to stumble.

avcwo

The tank is full. I actually saw your previous post on that. I filled it up right after I had the issue and still had it after. 93 octane, NO ethenol.

0Callaway Chris

Fuel pressure should NOT drop that quickly, and especially to zero.

The rest, as Scott explained, is good info, so sorry the other vendor didn't respond.

avcwo

What other things should I look at that could cause the fuel pressure drop? I mentioned all fuel related items that have been replaced. I have not changed any fuel lines to/from the tank, all the the way to the fuel rail. The interior of the tank is clean, and as I said the fuel pump been changed twice. Thank you in advance for any help you can give me !!!

0Callaway Chris

Why has the pump been changed twice?

avcwo

Troubleshooting process. Car was low on gas, So I foilled it and changed the pump as a precaution. What about the fuel pump relay, oil temp sensor, or ECM? Any input on those as possibilities? If so what would I see??

avcwo

Further troubleshooting: Changed fuel pump relay. APPEARED to fix boost problem...at least 5 for about 20 miles, then the problem returned. I did check fuel pressure at warm up. It was 42 lbs. at idle, which I believe is low for a Callaway. 48 lbs. at idle is what I was told is correct. I did note the boost stumbling was not nearly as severe and was occuring at boost pressures above about 40 hg Abs, vise 30. I have previously installed an adjustable fuel pressure regulator.

89onlyZ51

If you have access to a wideband o2 sensor, it would be really helpful in diagnosing your problem. You want to be really careful that you're not leaning out under boost as you could grenade the engine. Lacking that, a couple of other things to look for:

1) Does the engine run OK under boost at low rpms (~3k rpm) and get worse at higher rpm under boost (4k+)?
2) Any black smoke in the exhaust when the car is stumbling?

My guess is you have an air leak somewhere in your turbo plumbing. If it's between the MAF and turbo inlet, you'll run lean. If it's between the turbo outlet and throttle body, you'll run rich. 42-43lbs of fuel pressure at idle is fine.

avcwo

Im learning as I go here:

1. What can the O2 sensor tell me?

2. I have been careful not to even get close to WOT when this started to happen.

3. Sometimes boost (about 80-85%) of the time, under low RPM appears to be fine. it starts stumbling over over 3k rpm....after that I have not pushed it to get anywhere close to 4k rpm.

4. NO BLACK smoke at all under boost or anny other time. Engine has original 19k miles.

5. I'm going to swap out the MAF. I have a spare I know
is 100%.

6. Fuel pressure at Idle after being driven goes to 38 lbs.

7. All injectorr, except the CSI have been changed. I suspect possible leakdown. It is the original injector

8. NOT sure about the leak as all tubing gaskets have been replaced with new, and clamps have been upgraded to new turbo constant tension type clamps...but then again..maybe I missed something

PLEASE HELP

avcwo


[/I][/I]

avcwo

I drove my car with the microfueler disabled...This is what I found;

1. ANY acceleration over abouit 3k rpm causes hesitation/stumbling/bucking...This is true if the microfueler is enabled or not....same symptoms.

2. Swapped out the MAF. No effect at all.

3. Checked for leakage on all clamps/hoses. Found none.

The fact that there is no real change in whether the microfueler is on or off would indicate the microfueler is inoperable. Any acceleration over ~3k RPM, in boost condition or not, OR in boost at same rpm and over 30 in hg abs gets same poor outcome.

My plan next it to swap out th O2 sensor and replace the knock sensor, and coolant temp sensor. I have those parts. The coolant sensor is bad for sure (temp readout fluctuates from 299 to whatever.) I have had a code 43 fault (once) and swapped out the ESC. The knock sensor is next.


ANY HELP will be appreciated!!

avcwo

SurfnSun

Have you checked the boost line to the MF?

The other thing you can do is let the car idle and make the MF come on by supplying artificial boost and see if it floods the engine out.

0Callaway Chris

Sounds like you found the part is "bad". So back to the original question, "how to get it refurbished?" Any word from Bill Woods?

There are also more modern systems which are available to control auxiliary injectors. BoostedMaxPSI had success with one.

avcwo

Hi Chris,
NO WORD from Bill Woods. Do you have current contact info for him??

I will contact BoostedMaxPSI ASAP!!

BTW.. changed the MAF as well...no change..

Thanks Chris!!

avcwo

avcwo

I will be doing a continuity check of the electrical wiring and vacuum lines to the MF after the holidays. I DID check the 10 amp fuse and the fuse on the MF itself...both good

avcwo

Sorry Chris...it is BILL SHAW not Bill Woods...

0Callaway Chris

Bill Shaw's info is in your PM inbox.

avcwo

Called him. He is going to help me out by giving me ideas for MF replacement. He hasnt worked on them in years, but was very willing to help/advise me for alternatives.

Thanks! We will see what happens!!

KP

[/I]

89onlyZ51

Sounds like the microfueler isn't kicking in when it's supposed to. Since drivability is normal at

89onlyZ51

Sounds like the microfueler isn't kicking in when it's supposed to. Since drivability is normal at