Tech / General EngineWhy is my car making that sound? My car won't start! Combination questions? Don't see a board for your problem or have other technical or engine specific questions? Post them here!
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Know that I think about it.....Jessica hasn't posted any updates since she was adviced to get her VATS checked out.......So maybe thats 4 cars that have been fixed due to this thread....
We owe a Special Thankx to Brandon(Chevy8588) for helping US ALL out and the info and advice he gave FREELY...lol, to everyone.....On behalf of everyone....Thank You!
Great Jobs guys, bet many of your post to problems have resulted in fixes, I'm not going to speculate as to why results aren't reported!
This one progressed quickly because action was taken and results good, or bad were reported in a timely manner.
__________________ 88' IROCZ 388/6.4L TPI Motown 350/4-bolt main stoker, and then some.
i dont understand why people cant report results, even if it fixes i, its nice to follow up with us, this thread SHOULD in all reality be a sticky for all the random no starts out there to follow lol.
Great Jobs guys, bet many of your post to problems have resulted in fixes, I'm not going to speculate as to why results aren't reported!
This one progressed quickly because action was taken and results good, or bad were reported in a timely manner.
I checked yesturday and at 201 replies, it had something like 2500 veiws. I would like to think that many more cars were fixed by this thread!
the vat system only tells the injectors "no fire" in engine cranking mode. when the key is released to run mode the injectors should fire normally.idk if that's the culprit, but just offering what i know. good lukk
i dont understand why people cant report results, even if it fixes i, its nice to follow up with us, this thread SHOULD in all reality be a sticky for all the random no starts out there to follow lol.
it wasn't this exact thread that got my 90 rs back on the road after 1-1/2 yrs of dancin' with the VATS, but thanx for being here.
i'm currently chasing a " low charging " condition, and u've helped cut the guesswork tremendously.
new alt. with
const.(+) red wire at plug.
brown wire for activation go's on w/ ign.
new battery.
alt. bench tested at az. - o.k.
whole vehichle test shows charging at only 12.2v
any ideas? i'm just doing what i can to increase you success rate.lol
is the battery neg cable the only external ground in the charging system?
and i only read 12.2v on the output post on the rear of the alt.
would grnds and cables still b the culprit?
thanx TONS
the vat system only tells the injectors "no fire" in engine cranking mode. when the key is released to run mode the injectors should fire normally.idk if that's the culprit, but just offering what i know. good lukk
Sorry to cut in, but who are you talking too\giving advice too?
sorry, didn't realize there were hundreds of posts on this thread. way back near the begining there was a discussion on injectors not firing cause of vats module. i think they already solved prob.
i'm still kinda new, i'll go stand in the corner now.
lol @ standing in corner, and you're only getting 12 volts at the charging terminal? if your getting a signal @ the activation wire on the alt, then i would say that the voltage regulator inside the alternator is to blame, also there are 4 major grounds, bat to block, block to firewall and back by the bellhousing there are two grounds from the wiring harness. clean/repair/replace these, check for continuity in the + battery cable as well, and i'd say upgrade to a cs-144 140 amp alternator while you are doin all this. but a low charge condition and the alternator is only blasting 12 volts, it's USUALLY a bad voltage regulator, or the signal wire is not working and not waking the alternator up.
WileEcoyote,
I am having the same issues with my 89 firebird, 5.0 tpi 305. I have changed all of the random sensors, tested fuel pressure(47), changed injectors, dizzy, set timing, still can't figure out why my car wont start. I can spray starter fluid down the throat and she fires right up, idles great but when I accelerate there is a lot of hesitation.
I recently tested my throttle position sensor for voltage and it is at 4.75 at wot and drops down to 2.23v at the bottom end of the range. I was told that it should be around .45v at the low end and that is what is cutting the fuel to my engine at low rpms. It runs great once I get it up to 2,000 rpms. I am trying to figure out what sends the voltage to the tps. Maybe I have a bad ground? I have tried adjusting it and could not get it to go any lower than the 2.23 I was getting the first time. Let me know if your tps replacement helped or if you need to know how to test your old one.
Hey guys I am jumping into this late post late and i need ya'lls help... i have a 90 IROC 5.7 Auto TPI ( it origanally was a 5.0 TPI Auto ) I have owned this car twice the first time i got it when it had the 5.0 in it. the motor was done and i was going to swap it but time nor money never allowed me to do this, so i sold it to my buddie who had a bad *** 91 that he twisted the body on. He took all of the 91 Z28 stuff from the wrecked car and put it in mine including engine trans disc rear and computer. he also swaped the stock injectors out for a set of bosch pink tops. After he did the swap he decided that he was going to sell the car, So i jumped at the chance to get this car back. I drove the car home that night and it has set at my parents all summer... The car had way to much fuel being pumped into the engine due to the pink top injectors. the car would always start but would run like crap because it was loading up. i had a set of stock 350 injectors that i took to the speed shop and had them rebuilt cleaned and flow benched for me. I drove the car around to the garage to start the injector swap and then it happened... the car would just crank and crank and wouldnt fire. so i went ahead and did my injector swap thinking i will fix this no start issue later. well later is now. I try to start the car and it just cranks the security light is on and stays on, and i have 45 lbs of fuel pressure according to the gauge i put on the fuel rail. The car also cranks so i am not thinking it is a VATS issue. I dont have spark but i have 12V going in to the coil and coming out of the coil . the distributor was changed to a summit MSD knock off with the external coil. but i dont have spark. i have no clue why... any ideas would be greatfully appriciated! i will keep yall updated with my progress. I also know that i very well could have mis wired my fuel injectors because i didnt label which wire came off each injector, so any help on that would be great also.
WileEcoyote,
I recently tested my throttle position sensor for voltage and it is at 4.75 at wot and drops down to 2.23v at the bottom end of the range. I was told that it should be around .45v at the low end and that is what is cutting the fuel to my engine at low rpms. It runs great once I get it up to 2,000 rpms.
Well, the stock TPS setting should be 0.53v-0.55v. A setting of 0.45v is really lean and a setting of 0.63v is really rich. And I don't think its cutting fuel to your car at low rpms, I think you may be flooding it at 2.23v!
no spark? ignition control module! change that first! its inside the dizzy, dont worry about injector order, it's batch fire, each bank fires at once.
Ok, I have a MSD 6AL box that I was going to install but when you do that don't you remove the ICM anyway? If my memory is right that is what I did on my 79 Trans Am. Do you think this would work on the IROC?
Hey folks. I've been absent a while. Sounds like this thread is still helping a lot of people. Camaro_Doc, I agree with Chevy 8588. Mine was the magnet pickup in the distributor but the ignition module is a better first bet.
Guys - the 91 L98 is bugging me again. I let my son take the granddaughter for her first drive in the car (I'm supposed to sell it to her next spring because she fell in love with it on first sight) and he came back complaining about it dogging off the line. It would hesitate almost to the point of dying when first starting from a stop. It idles at about 450 once warm so I'm suspecting Idle Control Valve isn't keeping the RPM's up. But it also surges at low in town speeds. I've verified the complaint with a couple of test drives myself.
I may also have a Constant Velocity joint going out on the drive shaft. I can't think of the words to describe how it drives at 40 mph.
Drives great at highway speeds. But you have to slow down some time.
Paul - how's married life treating you? Still get some garage time occassionally?
any codes? dogging out could be injectors (wont trip code) Iac (wont trip code) ICM (wont trip code) or your TPS (may trip code, unlikely) and obviously your timing being way off, could be a an issue with the EST too, but the IAC does sound like a safe point to start
np, it SOUNDS like your IAC is stuck closed, because minimum idle with IAC closed in drive is 450 RPMS, so thats most likely it. also constant velocity joints are for front wheel drive cars only, i believe you are referring to a universal joint yes?, just make sure you get greasable ones, changing them is relevitvely easy
Hey folks. I've been absent a while. Sounds like this thread is still helping a lot of people. Camaro_Doc, I agree with Chevy 8588. Mine was the magnet pickup in the distributor but the ignition module is a better first bet.
Guys - the 91 L98 is bugging me again. I let my son take the granddaughter for her first drive in the car (I'm supposed to sell it to her next spring because she fell in love with it on first sight) and he came back complaining about it dogging off the line. It would hesitate almost to the point of dying when first starting from a stop. It idles at about 450 once warm so I'm suspecting Idle Control Valve isn't keeping the RPM's up. But it also surges at low in town speeds. I've verified the complaint with a couple of test drives myself.
I may also have a Constant Velocity joint going out on the drive shaft. I can't think of the words to describe how it drives at 40 mph.
Drives great at highway speeds. But you have to slow down some time.
Paul - how's married life treating you? Still get some garage time occassionally?
It's been great(marriage)! We are in Mexico as we speak/type! lol Yes I still get my ALONE time in the garage! LOL.
Now as for your problem! I had the exact same problem as you this past spring!!! It turned out to be the battery........Yes the battery! There was enough juice in it to start the car just fine. I really had no reason to question the battery, just a hunch. I avg a new battery about 3-4 yrs on the GTA! So I changed it(battery)...... that solved my "Dogging and Surging" problem!!!
P.S. I tested the old battery first.... 12.1v-12.5v I HAD NO CODES EITHER!
Last edited by y84pauloflondon; 11-11-2009 at 11:16 PM.
Well I have some input for this thread. About 5 years ago my 87 TPI car wouldn't start intermittedly, would jump and buck when it did run, throw different codes, tach jumped.....you name it. Drove me crazy. I followed the diagnostic tree, repaired the parts the codes were telling me to, all in all dropped about $500 in parts in it. Then the error codes started repeating on me.
So..........I noticed when it did start it would run good, then when it got warm the problems started. I replaced the mag pickup and was timing the car when it was still cold and when the car came up to temp I noticed the timing light would go on and off. I was losing spark. The engine would rev, drop back down, rev again, drop again. So thinking about it I realized that the car wasn't running on the computer when it was stone cold, but when it warmed up and the computer went into closed loop the probloems began. I pulled the diagnotics wire to drop the computer off line and bingo... she ran even when it was warm. So to make a really long story short I found the Comnputer/ESC ground wire on the back of the left cylinder head had a corroded terminal. Was hard to spot but I used a magnifying glass and saw the corrosion. I clipped the ring terminal off, soldered a new one on, and every single problem was fixed. I posted this about 5 years ago here and within a couple of days a dozen people posted and thanked me.
So............I know it's a long shot, but check the computer/ESC ground wire. Casued me no end of problems for several months and several tows home for a simple corroded terminal.
Also, why I think your battery went "Weak". Think of all those times where you couldn't get the car started, you were just cranking and cranking away....maybe! All those dead starts cut the battery life short!
i saw some post on here that seemed kinda like my problem but my car will run good for about 20 to 30 mins and then when i try to excelerate it is extremely slow at it if i go over 1500 rpms it barely moves at all its an 87 trans am 305 tpi didnt really see any answers on what some people did to fix this and r there wires on the back of the block that i cant see that migh be causeing this problem and yes before u ask i am getting a code and its 33
The wires I referred to are on the back of the drivers cylinder head. No gaurentee this is it, but only takes a few mins to make sure the bolt it tight and eliminate this potentail problem. You can use a mirror to check out to see if it's corroded.
Thinking about it..........I had a similar problem to yours, would not accellerate when it was warm. Turns out it was the EGR valve. No codes were thrown, so I used the GM service manual diagnostics tree and it led me to the egr valve.
Anyway.......just one of my experiances in the 23 years I've owned my car. And................just bought a second TPI car for my fiancee. Guess I'm a real glutten for punishment.
It was 50 this morning and 65 this afternoon...OK..soo..After the spark test I switched the fuel pump relays around..nothin..switched'em back...unhooked and hooked the battery..nothin....soooo...I took off the fuel cap and released teh pressure in the tank...put it on and VROOM..back to life...shut it down after 15min and started right back up...is it possible the vent is clogged somehow creating a vacuum lock after it sits? I am thinking I am smelling gas out the tailpipes from whatever is in the fuel rail when I crank it but then it starves itself.- Hawkdriver.
Well, I think we can rule out VATS.....Hawkdriver, have you read THIS thread? 5 other cars, with 5 Different problems have been fixed here!!!
It sounds like to me that you either have the same problem that WileECoyoteSr. had or the one I had with the MAF Power Relay. WileECoyoteSr was with his distributor.
Hawkdriver, read page 4 post #155. It's a brief discription of WileECoyoteSr problem. Also, try disconnecting your MAF sensor and then try starting your car, but do this when its acting up(Not Starting).
I will try the MAF sensor when it acts up...I am getting spark all the time which is confusing me. I can hear the fuel pump run....and once it's started once it will start all day. I have waited 3 hours between the last two starts today and it's kicked over. Although one time it cranked about 5 seconds then started. I'm really at a loss on this one. I took it out of storage and have changed the fuel pump, CTS, adjusted the TPS, cleaned the IAC, intake, and MAF, timed it, oil change, and new battery....so I hope this is the last gremlin before I leave Sunday. I don't believe it's the ignition module since I changed that about 6 months before I put it in storage...I also had just changed the distributor cap, rotor, plugs, and wires then too. I feel like there's a vapor lock going on...maybe at the charcoal filter or just plain in the tank not letting it push gas even though I hear the pump.
What exactly does the MAF power relay do during the start sequence?
BTW...I'm not getting any codes.
__________________ Justin
Flowmaster and K/N..otherwise...ALL STOCK!
22 years and still going strong.
Last edited by hawkdriver; 11-19-2009 at 09:30 PM.
hey guys !
sorry it's taken so long for the update (on my charging prob.) on my '90 RS...
constant (+) at alt.plug
activation wire HOT with key in run position
Changed cables-no help
double checked all the grounds-no help
everything pointed to the brand new alt.
took it back to a different A.Z. and told them i didn't want it bench tested- I want another new one.
sure as God made little green apples- the 2nd "new one " works fine. Problem #6 SOLVED ! THANX GUYS-You Rokk
grats on the working charging system! i dont buy autozone parts for THAT exact reason! I rebuild my alternators both of my cars have their FACTORY alternators in them! as for hawk, you cam have one of 3 issues, either the tank ven is clogged (most common) and not allowing internal pressures to equalize causing a vacuum for your pump to fight. or your evaporative emissions controll system is malfunctioning, be it a bad purge solenoid, or plugged charcoal canister, OR your exhaust is heating the tank, could be caused by a missing heat shield, or freshly done exhaust too close to the tank. get the tank pressure problem solved
It's not the heatshield because it does it when it's cold....I'm going to check the vent first since that's the easiest...how do I test the solenoid or check the charcoal canister?
__________________ Justin
Flowmaster and K/N..otherwise...ALL STOCK!
22 years and still going strong.
Now that you have given us more info, I agree with Chevy8588 and what HE thinks your problem is(3 issues), and not a problem with the MAF system since your not getting any codes. I had codes 33 and 34. Although when WileECoyoteSr was having problems, he to changed his distributor cap, and that did nothing. From what I understand his problem was inside the distributor itself! It would start fine for a couple days and then it wouldn't start at all for sometime too.
Have you tried testing the fuel pressure during start up AND while its running? Have you also taken a look at your fuel pressure regulator? One way to check it, is too remove the vacuum line off and smell it for gas fumes or actual gas in the vacuum line.
Hawkdriver, read page 4 post #155. It's a brief discription of WileECoyoteSr problem. Also, try disconnecting your MAF sensor and then try starting your car, but do this when its acting up(Not Starting).
Hi guys. Haven't been giving much attention to the Z-28 lately. Concentrating on still searching for a replacement management job. But I did get around to replacing the Idle Air Control Valve and that resolved the idle problem, of course. I haven't had time to measure the voltage on the TPS to adjust that and resolve the rich running.
With the air dams all around her, and it now being cold in Kansas I haven't had the motivation to put it up on jack stands to check the drive shaft U Joints or the Transmission and Axle mounts for that jerking feeling I occassionally get.
The car still seems to surge a little. But at least now it's driveable. I took my grandson just back from a tour with Disney on Ice in Japan to a neighboring city in it to look at a Craigslist 4th gen. Camaro he was interested in. That one wasn't right for him so we keep looking at 3rd and 4th generation cars. It's usually fun to shop when it's not your money but I am trying to help make sure he doesn't end up with a POS with the low budget he has.
Justin
