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C4 1984 - 1996 Tech/Performance
Thread TitleThread QuestionPosted ByPost DateReplies
C4 Injector Changeout I have a '87 C4 Coupe that I have owned for some 27+ years. Over the years I have made a few performance enhancements. Recently the car had begun to idle roughly and chalk up a "SES" light. With high mileage on the car I decided to make some maintenance parts service and upgrades. I installed a new IAC (Idle Air Control) unit, a Granatelli Adjustable MAF sensor, DUI Performance distributor, double roller timing chain, new spark plugs, and last but not least, Accel 24-lb Injectors. (I think 21or 22-lb were standard.) The car has had a Hypertech G2 early series power chip and Vortex air intake system with K&N filter on it for years. I still get a little rough idle and worst yet is when I shower down on it underload it seems have a pre-detonation or other misfiring sound and hesitation going on. Wondering if the early series power chip is not cut to work right with the new higher injector flow rate. Is there a later edition chip that would be recommended for the new inje... LD 6/2/2018 9:23:18 AM0
ERG - BACKPRESSURE THE EGR VALVE ON THE ENGINE OF MY 1996 BASE COUPE IS REPORTED TO BE A NEGATIVE BACKPRESSURE VALVE. I PLAN TO INSTALL EXHAUST CUTOUTS FORWARD OF THE MUFFLERS WHICH MAY IMPACT ERG PERFORMANCE WHEN OPENED. DO EXHAUST CUT OUTS IMPACT EGR AND CAUSE POOR ENGINE PERFORMANCE? IF SO, ARE THERE WORK AROUNDS OR SOLUTIONS THAT PRESERVE ENGINE PERFORMANCE? Ed Hill Ed Hill 1/22/2018 1:18:53 PM3
a/c problem My neighbor tells me that her 1996 vette's a/c does not work after starting the vehicle. After driving for awhile the a/c starts working, what could be the problem. thanks, Bob..Fl. Robert Johnson 8/15/2015 8:15:43 AM2
1978 Corvette Pace Car Hope someone can help me find 1978 Pace Car CB Radio Antenna. Have looked everywhere on internet and it seems to be discontinued item. Help! Thanks. wallyateal@yahoo.com' 315-558-2875 or 954-922-6785 Wally Arnold 11/5/2014 4:19:03 PM1
'95 ECM problems My '95 Corvette simply stopped working when using the key to start the engine. The Security light comes on, the battery is charged, the lights/windows all work...but the engine does not turn over. It has been in the shop (Bruce Chevrolet, Hillsboro, OR) for nine days. They can't find the problem. Suggestions welcomed!! Thanks... Mike Steele 6/30/2014 10:49:40 AM10
fuel injectors for 1985 I have a 85 Corvette (I'm the third owner) and I think I need to change the fuel injectors...as far as I know and I've owned the car for 23 years they are the original ones. How do I tell which ones to purchase for replacement? Ron 4/9/2014 2:46:18 PM1
1987 coupe Injector connector replacement I have some nicked and broken connector leads to my injectors. I am searching for a good source of replacement connectors and a basic rundown on the best method to perform the replacement, Any help is greatly appreciated. I really want to get back on the road and reliable. Dave David Coulson 7/29/2013 9:33:20 AM0
1985 4 + 3 transmission My transmission will not stay in overdrive. It has gotten more sensitive over time. Originally it would kick out of overdrive with fast acceleration or by using rocker switch. Is there an adjustment for this? Steve Meillier Steve Meillier 4/15/2013 8:08:51 PM4
bODY CONTROL MODULE I need a body control module for my 1995 corvette. The high beam indicator light on the dash does not come on and the failed maryand state inspection. I am trying to sell the car but I need the inspection for tage and my prospective buyer. Harry Geety 11/7/2012 11:42:04 AM0
Need '94 PCM Does anyone have a source for a '94-95 Power Control Module (PCM), GM part no. 88961148? Or a recommended remanufacturer to whom I could send mine? My '94 LT-1 auto laid up since July with faulty PCM, prepaid backorder thru GM for months, but remains out of stock with excuse of no cores to reman. Have spent months trying all sources from online to stores to other dealers, all same situation: out of stock. I did source one from Standard Ignition thru Netpatz.com but after $180 shop bill it was proved to be defective (Netpartz did do an excellent job of finding it, and also of return and refund). Anonymous 1/7/2012 12:04:41 PM6
C4 1991 Convertible Luggage Rack Needed Desperately! Help!!! We were recently the victims of a hit & run and we are having an extremely difficult time finding a relacement luggage rack. If you have any parts or the entire unit please contact Peter @ 561-654-1187. Thank you. Peter Victoria 9/21/2011 8:41:42 AM0
94 engine "surging" 94 all-stock LT-1 auto, 31k, engine just began "surging" continuously when stopped at lite. Outside temp in lo 90s, a/c on so eng temp about 230, where it usually runs in city traffic during warm weather with both fans running. Best description is that engine idle seems to be intermittently jumping up and down while waiting out the red lite, causing the engine to surge against the brakes. Pop the trans into neutral and engine settles down to calm, steady, normal idle. So the surging is only under the load experienced when stopped for lite with trans in drive. No other symptoms, e.g., when accelerating or at highway speeds. First thought was Optispark but nothing I've found regarding a failing Optispark matches these symptoms. Ring a bell with anyone? Thanks! Anonymous 7/10/2011 2:18:23 PM1
exhaust tips My 96 LT4 has a 3" Flowmaster (i think) with Flowmaster Racing mufflers. I intend to put the original system back on, but I want to change the tips to stainless or chrome. I don't see anything available other than a chrome cover that screws into the original. Does anyone know of a parts vendor? Also, looking for a buyer of theFlowmaster system. Thanks Mike Mike Bys 5/20/2011 1:07:44 PM0
1986 will not start I have 1986 that I park for the winter running,I took out of storage and now will not start,I checkout for spark it's ok check for fuel pressure it's 45-50psi,check for power at the injector no power.Will run if I spray fuel in the throttle body,check all fuses , ok. Louie Barrette 4/24/2011 6:17:53 PM1
1985 Corvette Tachometer I have an intermittent problem with the tachometer on my 1985. At times it works fine, then just goes to zero, stays there for awhile and then reads fine again. Does not work at all when the car is up to operating temperature. Works during warm-up. I checked the connections at the coil, in fact replaced the coil with an Accel unit, no change. Have any of you been through this problem? Thomas Shusko 2/17/2011 6:28:59 AM1
EGR Valve temp Switch I need a egr valve temp switch for my 85, L98. Looking for some leads as to where I can get one. Thanks for your help Nicholas J Popolano 10/7/2010 12:24:20 PM4
speed sensor problem on 1994 coup I recently made a hard stop and both, the ABS and ASR service / warning lights came on and stayed on. Local chevy dealer stated the vet had a faulty right front sensor, and when repaired the lights would go off. I purchased and installed the new wheel hub bearing ass'y complete with abs sensor yet the two lights remain on. Provided the new sensor is ok what does one do to cancel the lights? Dale Enloe 7/26/2010 8:52:28 PM0
HELP steady check engine no flash Hi I'm Joe and I need some help. I have a 1988 that has a steady check engine light. I was going to take the car for a ride a few days ago my idle was high (1400 rpm), the ses light was on and when I put it in gear the car stalls and shuts down. I've used two different code scanners and jumped the terminals and the light will not flash or communicate with any scan tools. I've followed the mitchell and all data diagnostic flow charts, I've used three new ecms and two new proms and the light will not flash. So I went to a junkyard and picked up a ecm and prom for a 1988 s-10 4cyl plugged it in and the light will flash code 12 only. Has anyone ever heard of this and if so how was this issue remedied. Joe Persico 6/28/2010 6:28:21 PM0
wet floor My 96 gets a water build up on the passengers side floor when it rains or I wash it. I know there is a drain but I can't find it. Any help? Mike Bys 6/11/2010 12:34:52 PM4
94 rough idle / low speed & med load misfire Took 94 LT1 out of winter storage. (used Stabil in fuel). Had rough idle. Refilled tank when 1/2 empty, problem persisted. Drained tank and refilled, problem persisted + low speed moderate load misfire whien OD kicks in at ~ 48 mph on moderate throttle. Down shifting and increased throttle results in engine normally -- so fuel flow seems ok. No warnings such as check engine. Ideas (MAF / O2)? Rod Simmons 4/16/2010 7:39:53 AM0
Bad odometer-or-Bad odometer motor Odometer on 1986 Corvette convertible with 49xxx miles operates intermittently. Sometimes it will not run when I start, but will operate o.k. during the drive. Sometimes it will operated o.k. when I start, but will stop during the drive. Sometimes it does neither and sometimes it does both! I have replaced the electric odometer motor and inspected the odometer gears and teeth. All appear normal. Anyone with similiar problems? What is the fix?? COL Jim 2/17/2010 12:49:04 AM1
1984 Corvett fuel pump wont run Have power new pump and relay fuel pump wont run Michael Whitener 2/4/2010 7:20:40 PM0
Bose Rear Speakers for C4 I am looking for 2 rear Bose speakers for my C4. Was told that the amps were blown (amps built into speakers). Jim Larsen 1/9/2009 11:41:17 AM4
C4 steering column 1985 I am tring to repair the steering column . I am at the point of reolacing the spring,i have tried to compress the spring ,but the column will not lock in place and keeps comming out, What can i do? Billy Baer 11/24/2008 3:02:35 PM0
engine miss when warmed up 1990 have a 1990 corvette base engine stock 40,000 miles. just changed plugs wires rotor cap pcv air & gas filter all A C delco parts. when the engine warms up to operating temperature the engine runs rough and stalls and runs as if it has a miss. What is wrong? replaced the PCM computer but no difference what is wrong?? cars its for months at a time hardly used Jay Levinson 7/5/2008 4:08:02 PM4
1990 Corvette Airbag System I am trying to find some more information on how to "repair" my 1990 Airbag System. The "clockspring" and all the necesseary parts, or computer changes, to get the seatbelt light, and inflatable restraint warning message to go out, and obtain a working Airbag System. Louis Wallen 5/18/2008 5:19:17 PM2
I need a good repair shop in Las Vegas for my 89 Corvette conv. I have an 89 C-4 conv. where one headlight doesn't go up all the way and the other is lazy by goes up but the lights do work. I would like to have a good & reasonably priced Vette repair facility in Las Vegas fix it for me. Also, my radio does not work & my antenna is stuck up. Anyone have a recommendation? Len Fiamingo 732-996-1040 Len Fiamingo 3/26/2008 7:59:07 AM2
1990 need hints on instrument panel lights staying on I have a 1990 convertible. I changed the convertible to the hard top and now the "inflatable restraint light" and the "seatbelt not fastened light" will not go off. Anyone heard of this one? The only electrical that was touched was to plug in the connectors for the rear window de-fogger. Lynn 10/4/2007 11:12:26 AM1
Need help with gauge cluster for 1987 c4 My oil pressure and temp jump back and forth automatically without my switching. Oil pressures gauge sometimes and sometimes does not. Volt meter spikes occasionally and panel lights dim off as if searching for a ground. Any suggestions? James Albano 9/4/2007 6:14:29 PM1
'95 Corvette Cooling System Need Help Please- Have changed water pump, thermostat, all hoses, radiator is circulating as it should, what else can I check? Car is still running 240-260+ Elaine Harris 6/26/2007 3:32:27 PM4
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