86WS6

iTrader: (1)

Hi, I have an 86 Trans AM with a 305 TPI. The car is all original with 31K miles on it. Often, but not always the car is difficult to start when cold. After the initial hard starting issue the engine runs perfect, and will start right up every time for the rest of the day. I drove this car 250 miles the previous weekend and other than the starting issues, the car ran great. This issue has been going on for a while. I had not delved into it because the fuel tank neck was cracked and the fuel tank would not hold pressure. This spring we replaced the tank and installed a new fuel pump while we had the tank out. The tank now holds pressure like it should, but the starting issue is unchanged. Obviously the two problems are unrelated. I have been reading the service manual for this car and believe that the Cold Start Valve, relay, or sensor that controls the valve may be the issue. Any thoughts as to if I am on the right track and how best to proceed figuring out which part is the problem? Thanks in advance.

eseibel67

Suspecting a problem with that crazy cold-start cuckoo clock setup is a logical thought. A quick easy check would be to see if the Cold Start Injector is getting power when it's supposed to. The system works on a timer (90 seconds? I forget) that is temperature related. With the engine ice cold and the ignition off, unplug the CSI connector. It's located on the mid-left side of the engine in the bottom of one of the TPI runner pipes. The 2-pin connector will have 2 wires - one tan and one purple. When the ignition is initially turned to "run", the purple wire should have battery voltage (13v?) and the tan wire should have ground. Remember that this circuit is time sensitive so be sure to get the connector and your volt meter all teed up before your assistant turns the key. Results of this non-intrusive test will determine the next step.


Although your car is very low mileage, it might also be prudent to ensure the distributor cap, rotor and wires are still in good shape. They can deteriorate with age. I assume you put in a new fuel filter after the tank was out, if not, change it. Also, if you haven't done it yet get the injectors cleaned. They have been soaking in various grades of fuel over the past 31 years and there will be some deposits on them whether the car has been driven or not.

Camaro86IrocZ

iTrader: (1)

Probably not your problem, but check your chip numbers, 1986 had some bugged proms -- http://www.gmtips.com/3rd-degree/dox/tips/ecm/prom.htm
Btw, mines doing the same thing, haven't had the time to look into to it to deeply yet so looking forward to the solution here..

86WS6

iTrader: (1)

It sounds like both of your suggestions should be checked out. The "bugged prom" issues don't match what is going on with my car, but it won't hurt to see if the issue was fixed previously or not. Since this memo is dated 1986, where it the world would one find a calibrator 30 years later? I think that the first place to start is to check out the cold start valve circuit to see if that part is working or not. This car idles very smooth, has excellent throttle response and no issues other then cold starting which does not seem to be affected by ambient temp or other conditions. Yes, the fuel filter has been changed, and the car gets a steady diet of 93 octane verified ethanol free fuel that I purchase from a local vendor who mostly caters to marine sales. True marine gas is ethanol free, and this dealer sells regular and premium grades. I also run Stable with every fill up. Even though the car does not have many miles on it, the car is started weekly and run for 30 minutes to an hour to ensure that it reaches full operating temperature.

paulo57509

What leads you to believe that it's the cold start valve? Did you go through the flow chart in the FSM for Chart A-9? Just asking so we don't cover stuff you've already done.

If you do this to check for voltage at the purple wire, don't worry about the timer. The timer is inside the cold start switch. BTW, the timer remains "on" for ~8 seconds max.

Also, the cold start injector circuit gets 12v only when the key is in the start position.

The cold start circuit is stand-alone and is not controlled by the ECM.

I'm not one to make the blanket statement, "Did you check the fuse?" for every electrical problem. But in this case, there is a crank (CRK) fuse that feeds the colds start injector circuit. Might want to check that.

86WS6

iTrader: (1)

Anyone used one of these prom adaptors? See the next post below for the link. According to this company the cold start valve is a common issue for these cars causing the exact problem that I am having, however in 1989 the prom was reprogramed to eliminate the cold start valve and allows the eight injectors to provide adequate fuel for cold starts. It sounds like this may be an easy quick fix to make the car start and run like it is supposed to. With the adaptor unplugging the cold start valve is the only mod required, and the wiring is left undisturbed. it also allows the fan temp control to be lowered to a desirable level and eliminate other potential problems later on. Considering how buggy these early TPI's can be, this does not seem like a bad idea.

86WS6

iTrader: (1)

http://tpiparts.net/inc/sdetail/11100/1495

86WS6

iTrader: (1)

From TPI Parts "86-89 TPI PROM Programming Service Price: $85.00 back add to cart PRM-089This is an economical service intended for stock or mild 1986-1989 TPI engines with ECM number 1227165. Fuel and spark advance tables are not modified, so there is no performance gain with this service as compared to stock. This service will not be optimal for you if you have a stroker engine, supercharger or turbo, or a non-stock camshaft. Contact us if you have any questions about whether or not this service suits your needs.You will not need to mail in your computer or current computer chip. We will program your settings onto an adapter that mounts between the factory prom and the ECM. This adapter will bypass the factory settings, and the ECM will run on the programmed settings instead. Please note that the factory prom must be mounted on the adapter for proper operation, and the factory prom is NOT included. You must use a factory prom that is originally from a 1986-1989 TPI application. If you have any doubts as to what its originally from, email us with the 4 letter code on the prom and we will try to find the original application.Turn around time is typically 1-2 business days. We can work with a variety of settings commonly used for retrofit TPI applications as well as for TPI Camaros/Firebirds/Corvettes:VATS Enable/Disable EGR Enable/Disable AIR (smog pump) Enable/Disable Injector Size Specify Size Fan On/Off Temperatures Specify Desired Temperatures Speed Limiter Specify Desired Speed RPM Limiter Specify Desired RPM Cold Start Injector Enable/Disable Cold Start Injector: GM used a cold start injector (also known as 9th injector) to provide extra fuel on cold starts on 85-88 models. In 1989, GM setup the PROM to add the extra fuel needed for cold starts, and eliminated the cold start injector. Eliminating the cold start injector is probably one of the most common changes needed on 86-89 proms. If you wish to have the cold start injector disabled, we will setup your adapter with the 1989 code, and make any needed changes on top of that. You will need to either A) disconnect the electrical connector to the cold start injector and leave everything in place, or B) physically remove the cold start injector from the runner and plug the runner hole with a cover plate. If you go with this method you will also need to plug the hole at the back of the fuel rail.Items for which no change is specified will be left in stock form. We will also need the following information about your vehicle: Vehicle Year Make/Model Transmission Type We can start with either a Camaro or Corvette binary file as a baseline on which to make changes. If you have aluminum heads (Corvette engines had alum. heads from the factory), we suggest going with the Corvette baseline as it has more aggressive fuel/spark tables. We don't suggest using the Corvette baseline on an iron headed engine.Disclaimer: Depending on the regulations in your state, it may be illegal to disable emissions. We assume that any request to disable emissions means that the vehicle will be for off-road use only. We are responsible only for providing a prom that is correct with regards to the requirements given. TPI PARTS shall in no event be liable in contract or tort (including negligence) for special, indirect, incidental, or consequential damages, such as, but not limited to, loss of property damage, or any other damages, costs or expenses which might be claimed as the result of the use of our products and services.The purchase of this service constitutes your agreement to the above terms."

TylerSteez

iTrader: (3)

I just ordered that chip for my 1986 ws6 trans am so I will gladly get back to you on if it helps my terrible cold start issue.

86WS6

iTrader: (1)

Thanks Tyler!

TylerSteez

iTrader: (3)

It's out for delivery today, once I get off work I'll put it in and try it out

86WS6

iTrader: (1)

I ordered one from TPI parts. It is also due any day for delivery.

TylerSteez

iTrader: (3)

Well I installed mine, it did help the start up but it is idling at 1500rpm now and missing when I rev the throttle.

86WS6

iTrader: (1)

Oh crap! Other issues? Did yours come from TPI Parts?

TylerSteez

iTrader: (3)

yep, tpi parts has been extremely helpful in their emails so far, very fast replies from them regarding other questions I've had so we will see how this goes

Edit: just figured out why it was fast idling and couldn't rev up. when unplugging the ninth injector from the harness I removed the pcv valve vacuum hose from the nipple it attaches to and forgot to hook it back up. not the chips fault.

86WS6

iTrader: (1)

I picked up the mail on my way to work last night, and my chip had arrived. I am looking forward to trying this out in the AM. Of course the only issue I am having with this car is intermittent difficult cold starts. Once the car is running and warmed up it will start all day long without problems. The instructions on the TPI Parts website says to unplug the cold start valve. This car lives for the 100 point charity car shows and shows as stock. It's not what one normally thinks of as a show car, but it is a survivor and it does pretty well in the 100 point shows. I am wondering if I can pull the cold start fuse and do the same thing? That way the engine will still appear as totally stock. I am going to e-mail TPI Parts and see what they think of that idea.

eseibel67

See post #5 above. There is no dedicated "cold start" fuse, the CSI system gets power from the "crank" fuse.


Disable the CSI circuit most easily as per supplier instructions and pull the connector the the CSI injector. For show purposes you can lay the connector close to the CSI injector. Or keep it plugged in and pull the connector on the CSI switch in the intake manifold since it's hidden under the flexible air intake.

86WS6

iTrader: (1)

The install of this adaptor from TPI parts is fairly straight forward. When removing the ECM it was discovered that the part is labeled with a different part number and a decal listing the ECM as a GM authorized remanufactured part. So, at some point the ECM was either exchanged in the recall, or failed and this remanufactured unit was installed. On first start the engine turned over a few times, then started right up. It will take some time before it will be apparent if this fixed the problem or not, since the cold start issue is intermittent. The car started without a check engine light, however the light illuminated within a few seconds of starting. The engine is running smoothly and idles about 100 RPM higher then it did before. I had to get ready for work so I shut the car off and left it for another day. This morning the car started up fairly easily. The engine turned over several times and then came to life. Upon a short test drive, it seems that the throttle response has improved, and the car seems to have picked up a few extra horses along the way. The car has more pick-up then before, easily smoking the 245R50 16 tires for about 30 feet, then barking the tires shifting into second gear. This car has never demonstrated this level of performance before. The check engine light stayed on through the entire run. Again, I had to back the car into the garage, as it was time to shower, go to bed, and get some sleep before another 12 hour shift tonight. Tuesday afternoon, the engine turned over three times and started up nicely. The check engine light did not come on. I don't know much about these systems, however it seems like it improves each time it is started. I know that my newer vehicles computer's learn and adjust anytime any changes are made. Do these TPI systems learn also? Overall I am happy with the purchase. We will see how it proves or disproves itself over time.

Camaro86IrocZ

iTrader: (1)

Thanks for the update as I'm on the fence with this mod.. Glad to hear it's working, not so glad to hear about the check engine light...

86WS6

iTrader: (1)

On my car the check engine light turned out to corrosion on the fuel pump relay causing a voltage drop to the fuel pump. All clearned up with new dialectic grease applied. Everything is perfect. So far, love this mod! The car starts and runs like a clock!

Camaro86IrocZ

iTrader: (1)

Did you make any other changes to the adapter besides the Cold Start Injector delete like change the fan turn on/off temps, ect.. ?

86WS6

iTrader: (1)

Fans on at 200, off at 190. Running a 195 thermostat. Disabled all ancillary functions to prevent potential future problems. My car already has a lock-up delay on the trans to prevent lockup until the car is moving 45 MPH and only in OD. The car is surprisingly responsive with what feels like increased torque. This is not supposed to be a performance inhancing mod. Maybe my car's performance had declined, and this has restored performance to previous levels?

ScarabChris

Have you guys been able to say with certainty that your hard cold start issue is resolved with that chip mod?

86WS6

iTrader: (1)

I believe so.The car usually starts without issue since the mod. At times the car can be a lititle difficult, but nothing like it was before. I need to drive this car more often. I believe that some of the car's personality is from sitting too much and old gas. These days the car starts everytime and will occasionally the check engine light will stay on. Switch it off and restart, and the light always goes off..Drive it a while then shut it down and it will start up and run perfect the next time we drive it.

Tuned Performance

iTrader: (92)

The check engine light on and ecm reset might be caused bye a bad ecm.

Vader

My '86 has no cold start problems. I modified the MEMCAL with a socket and installed a custom PROM a long time ago. I used the ARAP as a basis for programming so it has a cold start enrichment routine, eliminating the need for the cold start injector. I also altered the fan temps, TC lockups, spark tables, MAF tables, fan temperatures, EVAP and EGR temps, and several other areas I don't recall without looking into. I believe I had about $4 in the 27C256 PROM and a few bucks for the Pocket Programmer.