Hi everyone,

I have an 89 Camaro with the LO3 305 TBI engine. I've been having a problem with my car stalling out on me after I drive it for about 20 miles. I started noticing this when I drove to work and on the way back about the 20 mile mark it would stall. Once it stalls it starts back up but idles erratically and stalls out after a few seconds. But if you let it sit for about and hour you can start it up and drive it home.

So far I have replaced the distributor, TPS, Temp Sensor, Oxygen Sensor and checked for vacuum leaks along with making sure the timing is correct.

One last thing is that I can hear a motor grinding/winding sound coming from the TBI when it stalls out. Sort of an "errrr" sound as the engine comes to a stop.

Any ideas would be most appreciated!

 

Most likely hearing the iac valve.
I'd start by disabling the egr valve & drive it for a couple days.

 

i would take the throttle body apart make sure its nice and clean, carb cleaner doesn't hurt. check for gasket tears, maybe your fuel pressure regulator.. if everything looks good there then it wouldn't hurt to check your fuel pressure. 9-13 psi i believe is what you want to be getting. i just recently had problems with my 5.0 tbi. come to find out i had a tear in my gasket and some fuel was leaking into my throttle body just to keep it running. i fixed the gasket in my tbi and it made it run worse, due to low fuel pressure. replaced my fuel pump and she runs like a champ. good luck to you

 

I'm having the same problem with my 89 camaro and I have replaced a ton of parts thAt have made the car run better but has not fixed my problem including new ECM, all new vaccum lines, new coolant temp sensor, changed the tbi unit with a junkyard special and fuel filter and still the same thing

 

check your fuel pump relay and connector. it could be getting overheated. you need to determine what you are losing when this happens. You need 3 things to keep a vehicle running. Fuel, spark, compression. Compression isnt going to magically go away then come back. So it is spark or fuel.

 

Yeah I know what it takes but it hard to determine becaus it will not stall out sitting in the driveway only when I'm driving down the road. I would like to check the fuel pressure tho. Is there a quick connect some where on this tbi system?

 

im having the same problem did you ever figure out what it was?

 

no you have to connect to the lines somewhere. I think you can get an inline tester you put inline and then put a gauge on that. I dont have a link for it.

 

Stalling after 20 mile drive indicates that a component is heated and reached a critical temperature.

Two areas should be checked - fuel & ignition.

Fuel
If you have old, OE Fuel Pump the chances are that the hose between FP outlet port and gas tank feed through is leaking. As you drive fuel in the gas tank gets warmer and rubber hose softer - increasing a leak. Since this is inside the tank it is not possible to see it. Diagnostically fuel pressure check gauge should catch a very low pressure ~ 1 to 2 PSI reaching TB inlet port during engine stall. When engine is cold you're probably on the low side of 9 to 13 PSI spec, but enough to keep engine running. TBI system does not have a fuel pressure test port, but you can get a low cost TBI test gauge, for example Actron CP7817 with correct T fitting (part # 0180-000-1320).

Ignition
Symptoms like you're describing can also be attributed to intermittent reluctor coil in your dizzy or ICM. Very common for OE coil to develop corrosion and cause mysterious intermittent no start, stalling symptoms. Get a rebuilt dizzy or a newer spare one from JY and swap.

//RF

 

So I went through the the TBI and found that the gasket was leaking at the base where it meets the manifold. I replaced that and the car seemed to run ok for about a week. But the other day I went to start it up and it idles all over the place for a few seconds and then stalls out and dies. So I figured I would try replacing the IAC but no change. I guess I will check out the coil and fuel pressure. Any other suggestions for this?

 

That sounds like you have a vaccum leak if you look by ghe firewall thers gojng to b a little black plastic vaccum line look and see if it fell out i have the same problem acouple times and that fixed it

 

Your ignition module can do this to your car before it completely craps out.

 

I have the same problem... except I can drive pretty far before symptoms start happening. Around town, on smaller trips (less than 50 miles), its totally fine. Yesterday, I tried to do a 400 mile trip. 120 miles into the trip, during mid-day, I ran into traffic. On the roll to stop, when the engine was at idle, it died out on me. I could immediately restart. It ran for a few minutes, then died again. After a while, it would stall every 30 seconds or so. I finally pulled off, let it sit for about a half hour, and started it right up. Then, it would get me a few miles before stalling. I waited until about 5 (for the heat of the day to die down), and I finally started it up, and it drove another 250 miles without a hitch, at all... Not in traffic, not anywhere. I've had this before, and changed out the fuel pump and filter, and it did the same trip without a problem... A few months later, it is happening again. The only two common symptoms are that it happens when the engine is warm, and when it is hot outside and generally starts to do this stalling cycle initially after coming to an idle. I've replaced the fuel pump relay, fuel pump, fuel filter, and did a vacuum check. Additionally, I did a diagnostic on the TPS (within limits), solenoid (within limits). When this happens, the engine dies, the service engine light comes on, but there are no codes stored at all in the computer. I'm starting to wonder if it has something to do with the Emmissions system? Something about the fuel evaporating and backing up a valve or something?

 

how long has it been since youve changed the cap and rotor on the distributor?

 

Your engine stalling may be due to ICM module that is going bad or overheating. ICM = ignition control module is inside distributor in the back of the engine bay. Some non OE modules can be flaky at elevated engine bay temperatures (200F+) which what happens when you are in a stop and go traffic on a hot summer day. There is limited air flow to move heat out and TPI engines are notorious for eating-up ICM's.

I would get another ICM, preferably AC-Delco and install it after thoroughly cleaning mounting pad of old thermal heatsink compound. Too much thermal heatsink compound will result in a higher ICM operating temperature which you are trying to avoid in first place. A very thin, see through layer of compound should be used.

Happy Thanksgiving - just finished the dishes here....

//RF

 

I have not replaced the Distributor Cap, but I like the idea of replacing the ICM. This sounds pretty plausible. I just replaced the MAP sensor, and fuel filter (again) today. I'll pick up an ICM and change that out too. Have any of you replaced it? Should I go ahead and replace the cap, and all the internals too? Or just the ICM? What do you guys recommend?

 

The only other thing that may be causing intermittent starts (or loss of spark) is reluctor coil. Reluctor coil is a replacement for old ignition points. On a very high mileage cars or trucks moisture and road salt may accumulate and corrode coil wire windings. When you remove a distributor cap and it looks very cruddy there is a good chance that reluctor coil might be on its last legs. It plugs into ICM 2-pin internal contacts. When disconnecting this plug from ICM use care not to yank on coil wire leads, just unlatch white connector from ICM and pull by its body - not wires. This is what it looks like underneath. Note distributor gear has been removed and rotor shaft has been partially pulled out:



Replacing reluctor coil requires distributor removal from the engine and rotor shaft removal. By the time you get things dissembled, most people opt for a rebuilt dizzy with a warranty. In Photo below rotor shaft has been removed completely and coil plastic case is partially visible.




The coil (SMP LX342) and distributor reluctor (SMP LX372) are inexpensive, but getting things dissembled requires prying retention ring and replacing it with a new one which usually comes with new coil.

//RF

 

I have a TPI, & have been having a similar problem. I start the car just fine, & can let it sit in park or neutral and it will idle just fine. As soon as I begin driving & get less than a mile down the road, the rpms drop to 500 or less when I come to a stop. I put the car in neutral & have to lightly press the accelerator & hold the rpms around 900-1000. Turning on the lights, or running the AC/heat will delay the effect, & when the rpms drop it isn't as bad. When this happens it seems like the car is choking on too much fuel. I have replaced the air filter, plugs, wires, cap & rotor button, & ignition coil. My check engine light came on not too long before this happened, & the code tells me the Engine Temp Sensor is not working. I replaced that around 7-8 months ago. Thinking there's a wiring issue there. As far as the stalling I still need to check the IAC, but any other advise would be nice. Thanks

 

Alright, well, I got the chance to do some work on the car today, so I went ahead and replaced the distributor cap, rotor, ICM, PCV breather filter in the air intake housing, pcv valve, fuel filter and air filter. The distributor looked ok actually, but I went ahead and changed it. I drove quite a bit today and got it to start stalling before I made the changes, but it seemed to be running better after everything was changed and back together. At the same time, could just be that it was cold again.

I haven't changed the reflector coil, but I'll keep it in mind. This thing only has around 45,000 miles on it, and its been garaged its whole life, so there isn't much corrosion at all. I figure I'll see what happens over the next few days, since I've just finished throwing more parts at the problem. Honestly, I'm still concerned about the fuel filter. Theres quite a bit of particulate matter in the filter, and its only been 500 miles or so since I've changed the filter. I'm starting to wonder if I need to buy a new tank...

 

Anyone fixed their issue yet? My son has a 91 having similar issues. I disconnected the TPS and it runs fine but high RPM's. Replaced the TPS and the problem is still there. The fuel pump has already be replaced.