Hello Fellow Forum Members! I need to reach out to the mentorship of this organization to aid me in suggestions on how to get my 1989 back on the road.

Here is an overview; thank you in advance for your suggestions:

This car was a "gift" with the home I just bought. The previous owner said he was driving home one day and the car just died so he parked it under a carport and just parked it several years ago.

The car starts (with little/low engine power) and after a very few seconds (5-6) starts to backfire through the intake and loses all power. this gets worse very quickly and the car will not idle

Here are the steps I have taken so far:

Before trying to start the car the first time:
drained/replaced gasoline
removed/replaced spark plugs and sprayed lubricant into the combustion chamber(s)
replaced the fuel filter
replaced the oil and filter

After starting the first time and having problems noted above these are the additional steps taken:

checked the firing order
double checked the firing order
triple checked the firing order
replaced the plug wires
replaced the dist cap
replaced the coil
replaced the rotor
checked the intake and hoses for an intake leak

So after haven taken all the steps above i came across an article on the forum and decided that the timing chain had gotten slack, jumped a tooth (although the car only has 77k miles) and decided to replace it. I took everything apart yesterday and low and behold the timing marks line up perfectly (ie this isnt the problem).

The question is where do I go from here? Do I tear down the top end of the motor and have the heads re-manufactured while i have everything apart (do you have a post on how to do that ? Is there something else I overlooked that I should have done first?

Thanks much and happy holidays to all!

 

Timing chain problems are a thing of the distant past. Years ago they had nylon cam gears that would disintegrate over time. Since they went back to steel, you almost never hear of problems unless they have a gazzilion miles. Back to your problem, get a fuel pressure gauge (available at any auto parts store) and check your pressure. I'm guessing you have a) bad fuel pump, b) bad fuel pressure regulator, c) weak or bad injectors. Take the ignition module out of the distributer, its that black thing where the points used to be on earlier cars, and take it to Autozone (or the like) and have it tested.

 

put a vacume gauge on it my quess it is going to be flucating like crazy. But doing this will tell a lot post your results

 

..... ... Do all of the above , plus do an ohm check of all of the injectors ... with the electrical connector removed , test the two terminals in the injector ... you want to see around 16 ohms ... check cold and recheck hot ...........

 

The car was left there for you to swallow. Damn

 

Check for Broken Valve Springs!!!!!!!!

 

Compression check

 

Together with checking for proper fuel pressure, pull the pump out (easy to do) and check the fuel pick-up and sock. They could be gummed up, blocking fuel delivery.

 

So...a very stupid question....is there a check engine light flashing on your dash anywhere? If so then check for computer error codes.

I would also check for broken valve springs and do a compression check.

 

Please keep the suggestions coming... very much appreciated!

 

Based on your "symptoms", my money is on bad injectors (as others have speculated). The OE ones weren't built to handle ethanol. Any ohmmeter will do. Even the cheap one that you see "free with coupon" in those Harbor Freight ads will diagnose the problem for you.

 

My bet is on the ignition module. First, it starts and gets worse as the module heats up. Back fire indicates ignition timing change, seems to be electrical, mechanical problems don't change as engine heats up. Ignition modules fail with no warning.

 

Adjust The Valves

 

Also check your timing.

 

You should probably purchase a Field Service Manual (FSM) and follow the troubleshooting guide. This will allow you to diagnose your problem in a logical manner and prevent you having to "throw parts at it".
You might be able to find a used one here on the Forum in the Parts Wanted/For Sale section. The book will also help you diagnose future problems.
This eBay CD might be a good choice too. http://www.ebay.com/itm/1988-1989-1990-Chevrolet-Corvette-Service-Manual-CD-Repair-Shop-88-and-90-Wiring-/400613874220?pt=Motors_Manuals_Literature&hash=item5d46729a2c&vxp=mtr#ht_3138wt_936

 

First since you picked up the car for free, do yourself a favor and purchase the factory service manual for your year. It will contain a diagnostic tree for your problems so you can go step by step without just throwing parts at the car. Proper diagnosis the first time will save you time and money. The manuals are available from forum vendors (expensive) and used on Ebay and the forum parts for sale section.

Othewise, if you want to start replacing parts -
1. injectors;
2. fuel pump
3. fuel regulator
4. ICM
5. ECM
6. IAC
7. Oxygen sensor
8. etc. and on and on

Without the manuals it will get expensive quickly.

P.S. maybe someone with an '89 will read this and send you the diagnostic section dealing with this. Good Luck with the new car and its repair.

 

Oops, corvetteronw beat me to it while I was writing my response.

 

Also check to see if the harmonic balancer outer ring has slipped.

The timing mark should line up with the edge of one of the ribs, like so:

 

Sounds like a coil/ignition module to me. Borrow a code reader from AutoZone. If its electrical and bad it will pretty much throw a code. If no code, check fueling as suggested.

Good luck!

 

Hey everyone I wanted you to know that I have ordered the suggested test equipment (fuel pressure tester, ohm meter, and compression tester). Since I live on an island it is going to take a few weeks to get here. Once they arrive I will post an update. Stay tuned and thank you again for your suggestions!