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89 Reatta hesitates under power


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Hey my moms 1997 le sabre did the same thing if u use injector cleaner use two bottles the first will losen up the junk the second will blow it out. if that dosent work a repair shop has a snake they can use to really clean the injectors. two bottles worked fine for me<P>Brian

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clean the mass airflow sensor. it's located in the throttle body, 3 screws. remove it and use pressurized air to blow the dirt off the little sensing wires. to test for this, read MAF on the crt ecm data. should be 100+ at max throttle 1-2 shift. dirt will make this reading low, causing lean fuel mixture. p.s., this is a 007 top secret fix!! will also cause poor cold starting on 3.8c engines. fuel injectors can be tested, but you won't want to buy the equipment. have an injector balance test done if your concerned

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Read Canadian Girls post further down. Plug wires are probably original and might be in line for a change. Most of the other systems are relatively reliable but cleaning some of the sensors can't hurt.<P>------------------<BR>Hal, btk@vbe.com

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My 91 with 140k was getting a definite "chuggle" at 45 to 55mph under light throttle after about 15 miles of driving.All summer I had a bad rattle which I traced to the cat converter.Two weeks ago I had the converter replaced and the "chuggling" disappeard.I reason that what was loose in the cc was causing enough back pressure to cause the 02 sensor,while in closed loop, to send incorrect signals to the fuel system.My manual indicates that this exhaust pressure can be checked with a gauge at the 02 sensor port.I have not seen this problem noted on this BB,I post it for general interest.

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My wife's 89 Reatta V6 has approx. 80K miles on it and within the past three weeks it's developed a hesitation which is akin to surges and bucks. I guessed a fouled plug might be the cause so I replaced them. That didn't solve it. My web research indicates the problem could be fuel injectors. I've tried a can of injector cleaner but it hasn't seemed to help. Are the injectors something that I can replace myself? If they are, can you direct me where to find them and how to go about removing them? Can I test them in some way to determine if they really are the culprit? Thanks for your advice.<BR>Dale<BR>horqua@netscape.net

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If the car has an overdrive transmission (also called a four speed automatic) try this--at the speed it surges, take it out of overdrive and put it in third gear. See if that helps. <P>If so, does it ever try to die or feel as if it is going to die as you slow down coming off the freeway? If it does, get ready to buy a new transmission...you are probably loosing the torque converter. If you caught it early enough, you can flush the fluid and add a can of TransX, made by K & W. That will soften the seals and help the clutches work a little better. However, if it has gone on for some time, loosing the overdrive will eat up the entire transmission. <P>Sorry....hope it is only a fuel problem. <P>Joe<P>------------------<BR>1965 Wildcat Custom Convertible<BR>1970 GS coupe<BR>1990 Reatta coupe<BR>1999 Regal GSE<BR>2002 Reatta II coupe (I wish!)

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i think I have a similar problem here. My car idles sort of irratically and when accelerating off the line it will sometimes cough and stutter a bit. EVERYTHING on this car in brand new. New wires, coil pack, plugs, O2 sensor, fuel filter and intake and exhaust sytems. Nothing helps. the car runs well, has plenty of pep, gets reasonable gas mileage and is quiet and smooth over 2000 RPM. I've recently cleaned the MAF and fuel injectors. Nothing makes any difference at all. The car does this at all operating temps. I'm at a complete loss. I'm currenty thinking air leak in the intake or a bad MAP sensor, which i would replace (only $19), but I can't find it. I'm getting no codes, lights or anything else ou of the ordinary. There are no codes stored in memory either.

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I almost forgot, under moderate to full throttle from a standing start, the car exhibits characteristics more in line with a turbo or Honda with VTEC. At exactly 3350 RPM the power smacks you in the face. It's about as subtle as turning on the lights in a darkened room. At that RPM it puts you back in the seat and really moves. I have no problems with this (it's kinda cool), but I still don't think it's normal. It's just like turbo lag or the cams switching over on a VTEC Honda. I'm thinking this mystery power boost and the idling/stuttering problem are somehow related. Although the stuttering/idle problem is a fairly recent addition, the power surge has been there since I bought the car with 35,000 miles on it 2.5 years ago.<P>Oh yeah, it now has 74,000 miles on it.<p>[This message has been edited by Reatta VT (edited 12-15-2000).]

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Reatta VT, you don't happen to have an aftermarket chip in there, do you? I saw your post about your horsepower numbers and I was just wondering if maybe the fuel or advance curves take a big jump at that rpm. My larger throttle body makes mine a little "boggy" but after I had the injectors ultrasonically cleaned the rough idle went away.<P>------------------<BR>Hal, btk@vbe.com

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I do have an aftermarket chip, but the power surge characteristic has always been there, even before the chip. Stuttering and idle problem has occured since the addition of the chip. I've had the chip for over a year and the problems I'm having started only about three months ago. I've had the injectors removed, cleaned and flow tested in the last month. Everything seems to be in perfect working order. That's why I'm thinking it may be an air or vaccuum leak around the intake manifold.

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Were the heads milled when the port job was done? If so the intake would need milling also. The intake gaskets are a great design and would take quite a warp to cause a leak. The intake does have to be torqued down in several steps but I imagine you have a manual.<P>------------------<BR>Hal, btk@vbe.com

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Reatta VT, I think it would be best to address the "cough, studder" problem. It should DEFINETLY NOT do this. an aftermarket PROM may cause some weird idle/cold start problems, but a good engine should never backfire(i.e. cough). Not to belittle you, but the first thing to inspect on a waste spark type ignition system is with this problem is secondary ignition(plugs, wires, coil). look closely for carbon tracking. also, a good pointer is that the ignition module gets it's ground to fire the coils from it's mounting bracket. a weak ground here will cause ignition problems. remove the module and bracket and clean thoroughly. if it's not ignition, look at valves and guides. if it "coughs"(I take that to mean backfire, either through the intake or exaust, but usually intake) it means that somehow the intake charge is getting ignited. 88-89 Reatta's don't have a MAP, pretty sure 90+ don't either

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To answer other questions, no the heads were not milled, as the motor only had about 67,000 miles on it at the time, I didn't deem it necessary. I replaced all the gaskets(obviously) and made sure everything was done correctly, this was not a weekend project. I planned it all out and took my time so I wouldn't have an problems. I do not have a manual, but have access to a Riviera manual. The engines are exactly the same, so that should suffice. The engine doesn't really cough(backfire), perhaps that was the wrong word to use on my part. Just off idle until about 1800 it will "sometimes" miss noticably. The hesitation is only slight. The problem causes no drivability problems and is mostly just an irration to me. If I floor the pedal off the line it goes like crazy, no backfire or bogging at all. Just smokes the right front tire pretty good. There are no ignition problems that I can find, and I've looked A LOT. I checked all the connections with a multimeter, and everything was fine. The spark plugs are not fouled, there is no carbon trace and I've replaced the wires twice. It must be something else. It's been going on for so long now that I have become accustomed to and it doesn't really bother me anymore, but I'm a perfectionist, and I'd like to solve this mystery if possible. Even with all the mods I have done, it still averages about 23.5 MPG City/Highway, it runs great aside from that small miss on light acceleration.<P><BR>I haven't done any other mods in over 6 months. The car was perfect for at least 3 months after I finished. Therefore I don't believe any of these mods are directly to blame. I drove the car modified for about 6,000 miles without any problems.

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  • 2 weeks later...

I would check your TPS sencer. It might have a dead spot in it. If so it would not indicate your pressing on the gas pedal causing a lean condition and posabily a lean back fire in the intake. Then when it hits a good spot the car will take off. You need a volt/ohm meter and or a scanner to check/adj the new one. <P>If it has a MAF sencer that would be my next guess. They can give you crazy problems like that. You can try to clean it first (carefull of backfires). If it has the plastic one GM had a lot of trouble with them. There was a time when they were changing all 3.8 MAF 87-89 that were orignal just to be safe. <P>A intake leaking will be noticed if external. If internal (port to engine) the motor will want to die (when idling) when you remove the oil cap. Also it would consume oil, smoke, and have oil on one of the plugs. <P>The orignal plug wires are good for 60k miles. They could cause you problem after that. <P>The ecm can give you the crazyist problems. <BR>intermitants, backfires, run bad at certain time, etc..<P>This problem should be easy to figure out by a qualified tec. With out the equipment and eperiance you may be stabbing in the dark. <P>Tom

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Be sure and check the harmonic balancer. They are notorious for failure on the 3.8 engine. Your symptoms sound like a possible timing problem, but since the engine has the DIS ignition, and timing is completely managed by the ECM, the balancer is the only thing I can think of that would throw the engine timing off. <P>Good luck!<P>Joe<P>------------------<BR>1965 Wildcat Custom Convertible<BR>1970 GS coupe<BR>1990 Reatta coupe<BR>1999 Regal GSE<BR>2002 Reatta II coupe (I wish!)

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UPDATE: as of 01/02/01<BR>Car continues rough idle and hesitates upon acceleration with noticable lack of pick up. I've tried to change the fuel filter but I couldn't get to the top nuts and when I broke the seal on the bottom nuts it sprayed gas in my face. This is probably a task for an expert or someone with a hoist. I couldn't gain sufficient access to the filter to satisfactorily attempt changing it. My next plan is to follow Canadian Girl's advice and replace the plug wires. The cat converter seems to be tight and in place. I tried the transmission suggestion and that seemed to have a small effect, but I'm currently ruling out a transmission problem until I can solve the problem of the rough idle. I had the MAS replaced the week before this problem started and the repair shop assures me a new MAS should not cause this type of problem. (Is there any way I can verify that on my own?) I don't own a service manual so I haven't been able to figure out how to check the resistance on the fuel injectors as recommended by the shop doing the MAS repairs. I continue to check back at this site for other suggestions and all are appreciated.<BR>Greatfully,<BR>Dale

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If you suspect one bad cylinder, you can go to the diagnostic mode and enter the overide section. This will allow you to turn each injector on and off to see if the rough idle is confined to a single cylinder. This will help narrow the area you are looking at. It doesn't necessarily mean the injector is bad, it could still be a plug or more likely a plug wire. I found this from painful experience. If the problem started after the Mass Air Flow (MAF)sensor was replaced, I would certainly take a hard look at it. I am making an assumption this is what you mean by MAS as there is no sensor by that designation. You can try tapping the MAF sensor while the engine is running to see if it makes any difference. By the way, why was the MAF replaced? If it is defective you will have all kinds of driveability problems.<P>------------------<BR>Hal, btk@vbe.com

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When the harmonic balancers fail on Buick 3.8L the outside (pully side) slips from the inside. The crank position rings (inside)do not slip in relation to the crankshaft. <P>Tom

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Try unpluging the MAF sencer with the engine off. It will turn on the SES light and will not run right unpluged. But see if it runs better. If so maybe your new or rebuilt MAF sencer is bad. It happened to me. <P>Tom

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....hey guys thanks for the suggestion about cleaning the MAF sensor. Be care though....I own a Riviera and a Reatta....on the Rivi I sprayed Berkbile cleaner on the MAF sensor and the car started doing just what you're talking about (don't try this @ home).Incidently....the two motors are not the same if you look close. Get a Reatta manual.<BR> ....hummm you might also want to check the "Idle Air Control" Valve (or motor they call it sometimes). In the old days the idle air...particularly on start up was controlled by something called an "Automatic Choke". Now the computer in open loop regulates a thing called the "Idle Air Motor". The little valve inside does the same thing a "Choke Butterfly" used to do. Sometimes when they're old they tend to hang up "open" causing rough idling, surging, loss of power, etc. from the stuck valve bleeding too much air into the intake manifold from the air filter side. If it's stuck open it could surge a lean mixture into the combustion chamber acting like "turbo boost" burning the oil off the piston walls and shortening the life of the motor (throw you back in the seat though).<BR> Also ....when the tranny gets old it tends to "bogg" the motor at stop lights because the computer is holding the clutches engaged(some cheater service places will simply remove the wire to the tranny...thus solving the idle problem ....but causing the clutches to slip on normal driving...ie. no top end).<BR> ....if this sounds like balony...sorry...just trying to help....>>>>>>>>

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