Fuel Injection Problem

[l2sail]

Well I cleaned the plugs and it still will not even idle now, it will run on a few cylinders for 5 sec or so, not enough time to get over to the map sensor and check for vacuum. Im going backwards and I really havent done anything.

I double checked the TPI readings, they are just the opposite from what I read they should be. IE at idle I get almost 4v and at WOT its down to almost 0v. I tried for kicks holding just the TPI level so I got about .4v and then starting without applying any throttle and it still wont start.

Any suggestions?

[PathFinder 007]

A niod is just a 12 volt bulb with a connector on it so that it will easily plug into the connector that the injector plugs into. A 12v bulb or test light should do fine. I hear that you can find a noid at a local parts store for around $10.00, but even that much is alot for a one time test.

[benchtest]

There are a couple options to keep it running. 1 - get help. Someone that can keep it alive while you test. 2 - it sounds like it is running very rich, so creating a vacuum leak at the TBI could keep it alive. This, however, makes checking the MAP more difficult. The leak would need to be away from the MAP source. 3 - if you have a vacuum pump, you could apply a vacuum to the MAP and see if it leans out. Once plugs are carbon fouled they may not fire even after cleaning.

[l2sail]

Thanks, I got a syring today and will test map with that, also will test injector leads with the test lamp. Thanks for sticking with me. I am getting to the end of what I can do and Im considering taking it to a mechanic, Its probably something real simple but my digit head brain can recognize it.

~ Phil

[l2sail]

OK another update, I did another test on the MAP sensor, jumpering the power leads and reading the voltage on the sense lead I applied vacuum to it with a syringe and the volts dropped from 4.99 to 3.3 something. Not a calibrated test but does prove it goes down with vacuum.

Testing the leads going to the injector showed a very immedate and constant flash, very fast and the off time was no greater than the on. Doing it with the throttle pressed half and then full did not appear any different.

Watching the flow of fuel from the injector I can SEE it while the engine is idling, even collecting and dripping off of the butterfly valve. Applying any throttle cause a large pattern right off, almost like its going to full throttle spray.

Another observation, remember in the beginning I stated seeing vapor/smoke rising from the gasket between the throttle body and intake manifold, I was wrong, watching it tonight its coming from the gasket between the intake manifold and the exhaust manifold, yes thats what I said. I dont understand why there would be one there and the book doesnt show or describe it. Can this be a leak thats causing the problem? Why would there be a connection there?

This same vapor/smoke/fog will rise out of the throttle body after several attempts to start it or after it eventually stalls.

I discovered I can restart the car by disconnecting the injector leads and cranking till it starts and stalls from starvation. I can then get it to run for a few minutes....

Any Ideas??

[PathFinder 007]

Did you ever check to see if your manual tells you how to read the error codes stored in the ECU. Many vehicles have a procedure which will allow you to veiw the errors via a series of flashes by some designated display. My pathfinder has a diagnosis switch on the side of the ECU and a red and green led which will flash the error codes. My Plymouth Acclaim requires me to turn the key switch on and off in a particular sequence and the flashes the codes via the engine warning light on the dash. My mothers Cadilac actully displayed the numbers on her temperature display for her environmental controls on the dash. If your vehicle has such a setup, it would be worth it to find out what it can tell you. My Acclaims trouble codes covered just about every emissions sensor under the hood. As for your leak between the intake gasket and exhaust gasket, I don't know of any engine where the exhaust is directly connected to the intake except for through the EGR valve. If your engine is a four cylinder and the intake is above the exhaust and you have a minor leak in your intake gasket, fuel can leak down onto the exhaust manifold and as it heats by the exhaust, the fuel will burn off and be seen as smoke. Just another concern to watch for is if you have lots of raw fuel going into the cylinders and not being burned, it can end up in your crankcase and mix with your oil and then attack your seals. keep an eye on your oil level an maybe make sure your oil hasn't gotten thinned out to bad. Killed my father inlaws newly rebuilt 351 engine. I know that problems like this can be tough and you have to decide how far you are willing to go in finding the problem yourself. For me, I enjoy the learning that comes with resolveing my own issue and I figure I've also saved quite alot of money.

[l2sail]

Thanks for the idea, yes I have gotten the error code from the ECU, its was a three which by the book said it was a bad WOT switch (tested fine) or the closed idle switch which is part of the idle control solinoid and has too many wires to figure out which one is just the closed idle switch. The idle control solinoid appears to work so I didnt think that was it....

[PathFinder 007]

Using the electronics diagram in your manual should tell you exactly which two wires go to the idle cosed switch. If the ECU thinks the WOT swicth or idle closed switch are bad, it will not deliver fuel properly. It might be helpful if you list text on this thread for each error code that appears and maybe we (the readers who view your postings) can think of some things for you to check into. You need to eliminate the errors from the ECU by locating there cause. It also might be an idea to clear the errors from the ECU and see if they re-appear.

[l2sail]

Hi PF007 I do not have a wiring diagram, it doesnt come with the CHiltons manual. I have gone through the process of getting the error codes out and its as I said in the prev msg, a three. There are only a possible six codes, thats what the book says anyhow. Unless anyone has grand Idea Im going to bring it in to the garage. My only real thought is maybe the bottom of the intake manifold is OPEN and relys on the connection to the exhaust manifold to provide the bottom side of it, IE thats why there is a gasket between the two. If thats the case it beyond what I want to tear appart.

~ Phil

[benchtest]

I'm having no luck finding a picture showing your intake manifold. Haven't figured out that one yet. I hate to sound like a broken record, but is there good vacuum at the MAP sensor?

[l2sail]

That I dont know, how do you test for vacuum? Car wont stay running long enough to do much. I do know that putting a syring on the hose going to the MAP I can cause it to output a lower voltage. And I also sucked on the hose going in the other direction toward the engine and there is no resistance, can suck all I want and not build up any vacuum but I figued this was normal and you would only get vacuum whith the engine running.

~ Phil

[benchtest]

A vacuum gauge is the best method. You could apply a vacuum with the syringe and see if that reduces the injector spray. You can apply the vacuum before starting.

[l2sail]

Hi just an update for everyone who attempted to help me. I should have started with the basics, the garage found two valves sticking open, and adjusted them. The car is running now but is still running rich, getting about 24mpg and is rated for 30+ but ill live with it.

THanks

~ Phil