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4960 messages, Last post on Nov 25, 2009 at 8:23 AM

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#3286 of 4960 Re: Which engine is better ? [Mr_Shiftright] by qbrozen Mar 17, 2007 (11:05 am)
Replying to: Mr_Shiftright (Mar 17, 2007 11:00 am) geesh. i could imagine. probably couldn't put an electric start on that if you wanted to, huh? well, i guess you could, but it would take alot of heavy parts.
#3287 of 4960 3800 Series II SC idle fluctuations by dave8697 Mar 20, 2007 (3:57 pm)
I have a '96 Riviera that I have been trying to fix for 6 mos. I just fixed part of the problem last week but it still acts up, only not as often or as severely. At 142k miles the idle acted up. It would stumble while backing out of the parking space but not stall. Then I would give it gas and go and it would idle high but smooth out. It would idle high for miles and since I would get right on the interstate it would want to keep doing 65 on the hwy when I let off the gas. The code read VAF and/or MAF problems and I lost 5 mpg. I tried lots of fixes and then last week I removed the throttle body and think I found a broken gasket between it and the supercharger. I replaced the gasket and noticed a difference. My gas mileage is up from 23 to 28 mpg, which is what it gave me the first 2 1/2 years I had it. It still has all the same idle stumble and surge problems, except now only about every third or fourth time I drive the car. I'm satisfied with the 28 mpg now but I also have fluids accumulating on the intake manifold, under the supercharger. Coolant puddles on the top of the intake manifold towards the front of the engine (belts end) and engine oil puddles toward the rear. They don't get mixed. My oil looks OK and my coolant reservoir has a nice red color fluid in it. No brown gunk. Could I have a Supercharger to intake manifold gasket leak? Nothing ever leaks to the ground. Car has 156k miles now and is kept outside all winter (-9 F was coldest morning start this winter). The Dexcool is probably original (11 yrs old). I have chased this problem for 6 months and have replaced plugs, wires, PCV, coolant temp sensor, cleaned MAF and entire throttle body and plate with CRC spray, flushed trans, and checked SC oil. Air filter replaced again when I found gasket broken last week. I haven't taken out idle air control valve because the I was afraid to strip the screws. I sprayed the tip of it when Throttle body was off. I also never reset the codes. The other factor could be that I think I have a bad wheel sensor resulting from overheating from a siezed caliper. I replaced the caliper but I fear the sensor sends bad signals to the ECM. Some gasket leaks fluids out though, and I recently found that coolant does run through the supercharger to get to the throttle body for preheating. The EGR shows no signs of leakage where it goes into intake manifold. What needs to be done? I want to avoid really expensive repairs due to high mileage on car. Replies to this message: jipster (Mar 21, 2007 5:00 am) imidazol97 (Mar 28, 2007 5:48 pm)
#3288 of 4960 Re: 3800 Series II SC idle fluctuations [dave8697] by jipster Mar 21, 2007 (5:00 am)
Replying to: dave8697 (Mar 20, 2007 3:57 pm) Your Dexcool is 11 years old. Why haven't you changed it? You're not suppose to go over 5 years with Dexcool. You think about replacing the MAF sensor.. instead of just cleaning?
#3289 of 4960 3800 Series II SC idle fluctuations by dave8697 Mar 21, 2007 (6:27 pm)
Two good suggestions. how do I bleed the air out when I change the coolant? Should I use a gasket sealer additive in the new coolant? I can get a MAF sensor for $175 with a core exchange. You think that is the best next step considering the code set is P0102 related to MAF circuit. I stopped at Buick dealer today just before they closed and they said for $36 they will run a diagnostic check When I can come back. That didn't sound bad at all. They said it would not just be reading the code, which I know already. Should I give that a try before getting a MAF sensor? Or should I change the MAF first because 156,000 miles is near the end of a MAF sensor life anyway? When I got home I checked for loose bolts holding the supercharger on. They were all tight. Two bolts holding a small plate on top of SC were loose by about a full turn each. I will see if that changed anything tomorrow. Replies to this message: jipster (Mar 22, 2007 4:50 am) dave8697 (Mar 23, 2007 9:21 am) dave8697 (Mar 28, 2007 3:26 pm) and 3 more... imidazol97 (Mar 22, 2007 5:10 am) dave8697 (Mar 22, 2007 10:44 am)
#3290 of 4960 Re: 3800 Series II SC idle fluctuations [dave8697] by jipster Mar 22, 2007 (4:50 am)
Replying to: dave8697 (Mar 21, 2007 6:27 pm) how do I bleed the air out when I change the coolant? Open the coolant air bleed valve, there is only one,it's located on the thermostat housing. When you're filling the radiator, if coolant starts coming out of valve close it..otherwise close the valve after the radiator is full. I don't know about the additive.. the manual states it unnecessary and "may be harmful". I always say if it ain't broke don't fix it... so up to you on that one. But, the Dexcool is suppose to be changed every 5 years or 150,000 miles, whichever comes first. Some people here recommend sooner than 5 years. Heck, I would proably just change the MAF sensor. I had a free diagnostic code test done free at our local Autozone... code read the problem with the MAF. The dealership wanted $89 to run the diagnostic test and diagnoise to pinpoint problem. I was in a bit of a bind time wise and had them go ahead and do the test, then replace the MAF sensor on my Buick Regal LS. My car was cutting out though on occasion at stop light and slow braking. Anyhow, hope you can get things squared away. Replies to this message: dave8697 (Mar 23, 2007 9:21 am) dave8697 (Mar 28, 2007 3:26 pm) imidazol97 (Mar 28, 2007 4:24 pm) and 1 more... dave8697 (May 02, 2007 9:12 pm)
#3291 of 4960 Re: 3800 Series II SC idle fluctuations [dave8697] by imidazol97 Mar 22, 2007 (5:10 am)
Replying to: dave8697 (Mar 21, 2007 6:27 pm) You don't say what car model and what year. I know on my 3800s the service manual says to fill, you can use the bleeder screw to purge air if you want. Run the motor until the lower radiator hose is warm indicating a flow through thermostat and then run motor at 2500 rpm 5 times for a several seconds. That will move water through the system, and the heater core, to move air out to the bleeder screw area and into the radiator where it purges to the reservoir naturally. Then you can bleed again at the screw to remove all the air. It's important to remove all the air because one factor in deterioration of DexCool is mixing with air as it's moving through the motor and radiator. Some people recommend changing DexCool every two years or 24-36 K miles just like the abrasive green stuff. DexCool has many good properties that conserve aluminum and other parts of the cooling system. Early seals on 3800 parts in 97 or so were changed in composition because they reacted with DexCool after it deteriorated. MAF sensor can be removed. I've heard a mechanic talk about cleaning the wire very, very gently like with an artist's brush. If you look at it under magnification it will have dirt particles growing off of it like hairs. But the wire is extremely fragile. Replies to this message: dave8697 (Mar 22, 2007 10:44 am)
#3292 of 4960 78 mb piston lube problem by uteoat Mar 22, 2007 (6:58 am)
I'm in the middle of rebuilding a mercedes 123 diesel. There are no oil jets in this one as described in the book. Looking further I have found no oil passage in the conrods. The engine was recently rebuilt and the conrod numbers don't match up with the corresponding cylinders, so they might have been replaced. My question is how does the oil cooled piston get the lubrication it needs if there is no way for the oil to get to it? I,ve posted in other forums to try to get this question answered and am hoping there is some mechanical genius out there that can help me out with this one. Any and all help would be greatly appreciated. Thanks, uteoat
#3293 of 4960 Re: 3800 Series II SC idle fluctuations [imidazol97] by dave8697 Mar 22, 2007 (10:44 am)
Replying to: imidazol97 (Mar 22, 2007 5:10 am) It is a '96 Riviera. I will bleed the coolant fitting tonite to check if I have had air in the system ever since I changed out the coolant temp sensor. After that I will use a fine brush on the MAF along with the CRC electrical spray. The bolts on the 3-way vacuum fitting on the supercharger that I tightened last nite may have done something. No idle fluctuations in 3 trips today so far but way too early to tell.
#3294 of 4960 high idle by john_doe_wny Mar 22, 2007 (1:02 pm)
Hi, I have a 98 Taurus w/dohc with 123000 miles and at start up it idles high. Doesn't matter if engine is warm or not. 1500-1800rpm. Once I've tapped the gas it idles down and is fine. This happens winter or summer so outside temp doesn't really bother it. The check engine light doesn't come on. Once I've tapped the gas or the car is in gear it idles fine. (even in park after it's been in gear it's fine) I've used bottled gas cleaners but no help. Any thoughts would be great. Replies to this message: dave8697 (Mar 23, 2007 9:08 am) john_doe_wny (Mar 23, 2007 9:47 am)
#3295 of 4960 Re: high idle [john_doe_wny] by dave8697 Mar 23, 2007 (9:08 am)
Replying to: john_doe_wny (Mar 22, 2007 1:02 pm) The things that caused me high idle were gaskets gone bad that could only be corrected with gasket replacement. If you can tap it down like my '86 ciera then maybe it should go down by itself. Try cleaning and oiling the cam off the throttle plate. spray the linkages with wd-40. There could be a vacuum diaphram that pushes a link to kick it off hi idle. the vacuum line could be leaking or the diaphram bad. Check the throttle cables for interference including from the cruise control unit. Have you cleaned the throttle plate axle with gumout? That could hang it up too. My '86 Ciera idle is always high now too and it's probably the mixture control solenoid inside the electronic carb. I have to get a new solenoid for it. Going to the junkyard today. Found a new one for $96 but I hate to spend that much on a 21 year old car. I replaced this part for my '84 Camaro once and it did the trick, restoring about 8 mpg. The Ciera has dropped from 28 down to 22 mpg as the solenoid went bad. The bad solenoid always lets it run super rich and it's also ruining the new cat converter too. Replies to this message: john_doe_wny (Mar 23, 2007 9:47 am)