just so this is in the right topic area I have had a previous post on my car its a 2002 SSEi in the shed light on the situation from the start... Test drove fine except brakes were bad had dealer replace them ...picked the car up when paperwork was complete... filled up at the station and at the time I used regular( come to find out it premium only) ...I drive home from the dealer without a problem I did punch it a couple times (another mistake with reg in the tank)...it was an hour drive from dealer to home without a problem then as I was making a turn off the highway ( no off ramp straight off highway hard right turn) and in mid turn the car stalls if someone would have been sitting at my road waiting at the stop sign I would have hit them... I tugged the steering wheel to get back in my lane and then to shoulder put the car in neutral turned the car off and said WTF turned the key and car started right up... Got to my driveway and it stalled again when I let off the gas pedal and it has done this for about 4 months when I come to stop sign or stop lights and in that allotted time more problems have presented themselves one being seems to not wanna shift when leaving a light I'll be at 25 mph with 4000 rpms and I'm not pressing the pedal hard at all if I want it to shift I have to let off or press down another problem around 60 my boost gauge will jump around and my car seems to have a seizure it just tugs and lets off rapidly and the final problem at idle my engine will rock when my boost goes from -10 to -4...this seems like double dipping but their are pms I'm getting from others asking what exactly is going on I've had it at GM they full GPS and MAF since our codes replace them twice still getting the codes only codes that will pop up I've noticed a few discrepancies with the car like wires being spliced at alternator which I've ordered a new engine harness from BonnevillesUnlimited.com I believe ran by harofreak which he gave me a sweet deal thanks again but I've had around a grand(a lil over ) put into trying to figure this out I appreciate any and all assistance I'm and proud to be part of a (I guess I would call it) community of people who gladly reach out to help other in need thanks again guys and girls

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Never getting rid of my Bonnie

Check, double check and triple check for vacuum leaks, pay particular attention to the fittings as they like to get brittle and crack, the T fitting under the snout of the supercharger is a common problem child.

Does the transmission fluid smell burnt or look burnt / brown?

When the car stalls, do the lights go out as well or the engine just stop running and literally nothing else changes?

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Ryan

2003 Bonneville SSEi - The Black Mirror SOLD!
2002 Bonneville SE - The Mutt Complete 2004 SLE interior, drivetrain, and body harness swap, ECC swap, HUD swap, black GXP wheels, GXP headlights and tinted tails - SOLD
2003 BMW 540i M Sport, 2001 BMW X5 4.4i, 2010 GMC Acadia, 2017 Grand Design Imagine 3150BH
1982 Cutlass Supreme - The fun one

Transmission fluid looks good but I'm no expert and when it stalls brakes go out power steering goes out and engine shuts off lights stay on on dash instruments

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Never getting rid of my Bonnie

Trans fluid is easy to assess. Red is good. Brownish and burnt smell is bad.

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-Car Guy Carl
"Penelope" - 2003 SLE - 250k Miles
"Sydney" - 2000 Honda S2000 - 101k miles

It's red... I seen it the other day when I was adding some lucas tranny fix

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Never getting rid of my Bonnie

Have you replaced the crank position sensor, or the ignition control module?

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-Car Guy Carl
"Penelope" - 2003 SLE - 250k Miles
"Sydney" - 2000 Honda S2000 - 101k miles

No but I planned on replacing a lot of that so I don't mind buying the parts I just want to have car running normal my average mpg is 19 right now and I drive all highway I've tested the icm I've checked the pcm cleaned out the connections tried the carb cleaner to check for vac leaks...however the cps has been on my mind cause I read a lot of post about them getting heat soaked and the stalling happens more often when at normal operating temperature I recently bought an inspection mirror so I can look at it unfortunately I can't work on it til weekends cause of work

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Never getting rid of my Bonnie

I'd replace the CPS with a good one, and potentially swap out the ICM to a known good one as well, just in case.

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-Car Guy Carl
"Penelope" - 2003 SLE - 250k Miles
"Sydney" - 2000 Honda S2000 - 101k miles

Alright cps icm are on my to get list I won't be able to get it til next Friday... Should I get new coils also I haven't test those but they all crackled with sparks when I lifted cable boots

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Never getting rid of my Bonnie

If a coil is bad, you'll likely get a misfire code at the cylinders that it operates. I think they're fine, from what you're saying.

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-Car Guy Carl
"Penelope" - 2003 SLE - 250k Miles
"Sydney" - 2000 Honda S2000 - 101k miles

Yeah that's the strange part the only codes that come up I've replaced at first it cause me to think the pcm was bad cause it wasn't getting what was wrong right... I work on spas and is we get a HI code and we switch the High Limit switch and it still throws that code we then check fuses if all multimeter test come back norm we switch the board and all is good meaning that the board was defective but that didn't seem to be the case with my pcm so I was baffled that tps and maf kept popping up after being replaced

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Never getting rid of my Bonnie

Check fuel pressure you be surprised on how much it will make most of the sensor 's run a muck i had a similar problems found out pump was going bad its really easy to check on your own.

Checking fuel pressure makes sense, should have around 52-54 key on, engine off and about 44 at an idle. Then at the blip of the throttle it should bounce back up to 52-54. Fuel pump should also hold pressure while the engine is off.

Someone can correct me if any of my numbers are wrong, but I think they are pretty close.

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They ran that test at GM of course they didn't provide me with any stats but they say fuel pressure was good but I'll run another test myself what equipment will I need

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Never getting rid of my Bonnie

Something that's been on my mind what can be damaged by using regular fuel instead of premium

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Never getting rid of my Bonnie

since lower octane gas burns faster, you get knock from using regular. The PCM will retard the timing to compensate, but under wide open throttle this may not help, and detonation can damage to pistons over itme. One tank probably will not do any damage if you take it easy but once you are down to 1/2 tank, fill up with premium to raise the octane rating of the mix, then keep using premium gas after that.

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bobgto65

2004 Bonneville GXP 62,000 miles purchased 04/13
2009 G8 GXP PBM, M6 9580 miles, no mods, sold 08/15
2009 G8 GT SBM 36,000 miles, modded 430 whp
2002 Bonneville SSEi 203,200 miles (sold 3/2014)

Oh I only used regular for like two or three tanks I've used premium ever since its been four months I sea foamed it with only half bottle through tank then I've been using injection cleaner every now and then and only one fuel system treatment I even changed the fuel filter I assumed that would be enough to clean the regular out

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Never getting rid of my Bonnie

I have a 2000 ssei & original owner kept the window sticker and it says 87 octane only don't know if the higher octane would really make a difference

Apparently at higher speeds it's needed for the proper combustion in the chambers something I'm trying to comprehend is the difference between lower octane rating vs higher rating....but to update the situation I found that my MAP sensor plug that connects to the throttle body was brittle I Jimmy rigged it with two different size silicone tubing and my engine light has been off for three days and problems have not presented themselves...so I got to ask would the MAP sensor cause improper reading for tps and maf I would think it would

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Never getting rid of my Bonnie

That doesn't seem right to me for the supercharged engine. It seems like I remember my grandparents older Buick Park Avenue Ultra that was supercharged requiring premium fuel only and they traded it in on the 01 SSEI I'm driving now.

I know mine either says premium on the dash or behind the fuel door, but I had KR in stock trim running 91 octane. I can't imagine trying to run one of these cars hard on low grade gas, say climbing a steep grade while the torque converter is locked up.

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