mxdirtking

I just swaped out my 2.8 v6 in my 87 camaro and put in a 305 TPI out of an 85 TA. I got it all in and we got it fired out but when you go to hit the throttle it cuts out every time you hit the throttle even when you feather into it but it idles fine and everything. I unplugged the TPS and that didn't work but i still have the same fuel pump in it when the v6 was in it but the v6 is fuel injected to but people are saying that I need to change the fuel pump. I have not hooked up all the vaccum lines tho and that could be a problem but it runs fine with them plugged but I do have the fuel pressure regulator vaccum line connected. So if I could get an answers or ideas would help im just stupped right now and cant figure it out.

Thanks, mxdirtking

five7kid

iTrader: (14)

Welcome aboard thirdgen.org.

The V6 pump can't provide the required volume for TPI, but that's more of a wide-open-throttle issue. I'd suggest you get a fuel pressure gauge and see what the fuel pressure is doing when the engine acts up.

Is the SES light coming on?

mxdirtking

Yeah I just ordered a fuel pump for it, for the TPI and im going to check the pressure hopful tonight if I can get a hold of a fuel pressure gauge.

mxdirtking

My SES light is on but I think it is on because I got a Painless Wiring Harness for the swap and I didn't hook up the speed sensor, oxygen sensor, VATS, brake switch, and the knock sensor which im going to hook it up tonight. It doesnt have an EGR valve either but I dont think that would do it. Do you think my fuel pressure regulater could be shot?

Thanks, mxdirtking

Air_Adam

Almost all of those can set off the SES light.

mxdirtking

Yes but I dont think that any of them would make my engine cut out when I go to touch the gas. I just don't get why the motor will run fine when idling and when you go to touch the gas, feather it or anything it will cut out like as soon as you hit the gas but once you let off it goes back to idling just fine. So its got to be fuel supply pressure or something on the throttle body and I dont have the vaccum lines hooked up on the throttle body either so that could be a problem but they are plugged for now.

mxdirtking

I had 41 p.s.i on the rail when just turning the ignition on without the motor running.

mxdirtking

I dont think that it is fuel related at all because I changed out the fuel pressure regulator and that didn't do it. I thinks it could be the MAF sensor. I unpluged it and you could rev it but it was still cutting out but that could because I don't have the sensor plugged in. Any help or ideas would be great!

Thanks, mxdirtking

waybud

The Knock sensor will make the engine cut out...Hook it back up...Check your CTS (Coolant Tempature Sensor) for resistance ....The voltage reading should be 5 volts coming out cold and should drop as the engine warms up. this will directly affect your MAP sensor.... It should read 5 volts at idle and drop as your reve the engine. I don't remember if this model has a crank sensor but check it for proper operation if it does...The throttle position sensor can affect the operation too. These are just a few items to check before driving yourself nuts.

mxdirtking

I hooked the knock sensor up did the same. I unplugged the TPS to see if it helped and it didn't. But ill check the CTS to see if I get 5 volts but its a brand new wiring harness but it doesn't hurt to check it. Thanks waybud!

ASE doc

Any sensor in the system will read 5 volts, only when the circuit is open. If the ECM sees any sensor input at 5v, it will set a code for "signal high". MAP voltage should read about 1.6 at idle and reach about 4.5 at atmosphere(no vacuum). However, MAP doesnt really apply since, unless youre using a later model or aftermarket FI system, your 87 is a MAF car. MAF cars dont have MAP sensors. MAF voltage runs about the same as MAP voltage. About 1.6 at idle, 4.5 at WOT. I suspect that your symptom is caused by a MAF problem. Also, check carefully for any vacuum leaks. Granted a vacuum leak has to be bad to cause a cutout but check to be sure anyway.

The knock sensor will not make your engine cutout no matter what is wrong with it. The knock sensor circuit simply commands the ECM to retard timing in the presence of detonation. Retarded timing will decrease power but not cause a cutout.

The OE does not provide CTS voltage for diag purposes. You are supposed to use a scan tool when diagnosing the CTS circuit. CTS resistance should be 1,800ohms at 100f and 3,400ohms at 70f.

You have just installed a complete FI system in your car. You need to have the proper equipment to verify proper operation and pinpoint any issues. A Snap On Brick(the perfect scanner for the 3rd gen) can be had for $300 on Craig's List. I strongly urge you to purchase one. Be sure it has working domestic software and GM1 DLC interface with power cable.

mxdirtking

I checked for codes tonight and I got 3 codes. Code 21 (TPS), Code 33 (MAF high), and Code 42 (EST). So i cleaned the MAF sensor and its still running funny and the TPS would be why it is cutting out all the time and I don't know about the EST (electric spark timing) it doesn't seem to miss at all but when it is idling it backfires once in awhile but that could be from the bad MAF sensor. Im just going to replace the MAF sensor and TPS and thanks ASE doc for the information.

Thanks, mxdirtking

ASE doc

Before you replace the MAF sensor(a good one isnt cheap), perform the test sequence for your MAF code. The problem with MAF systems often is not the sensor but wiring and/or one of the relays.

TPS will cause a cutout on throttle openning due to the loss of asyncronous injector pulses, which serve the same purpose as an accelerator pump in a carb by compensating for the sudden increase in air as the throttle is openned. However, this affect is only temporary, resulting in a severe hesitation where the engine falls on its face when you step on it, then springs to life throwing you back in the seat as MAF fuel enrichment catches up to the increased air.

mxdirtking

I has a brand new wiring harness when I swapped out the motors and I used the same relays off of the v6 and it ran fine before I did the swap. Can you adjust the TPS or do I just replace it?

ASE doc

The TPS is adjustable but I dont think thats going to help you. I fear that youre stabbing away in the dark. The first thing I do after any major repair on a fuel injected vehicle is connect a scan tool and look at data and watch for any codes to set. This tells me, before driving the vehicle if Ive left anything disconnected or have any wiring/component issues. I would feel a little lost right now in your shoes. Not knowing what my sensors are reading or if my ECM is even functioning correctly.

As I said the TPS will cause a hesitation but only momentarily. TPS hesitation is troublesome because the car falls on its face then immediately breaks the tires loose as it recovers. Its like a bad accelerator pump in a carbuerator. An engine that falls on its face and stays there is caused by the MAF sensor, loss of fuel pressure, loss of injector pulse, ignition system issues can cause this kind of problem. But not likely TPS. Not unless TPS signal is just completely dropping off and Ive never seen that.

My point is, you really need to invest in proper diagnostic equipment. Or for that matter beg or borrow it from a freind. You need to see what your ECM is seeing and what its doing.

mxdirtking

Hey ASE doc I got a new MAF sensor and TPS sensor and put them on and when you hit the throttle it doesn't cut out like it did but its still not running right so I did the cods and got codw 33 (MAF sensor (high)) and code 42 (elecronic spark timing). It seems to backfire alot now and someone told me that when I unplug the computer that I have to reset it with a diagnostic tool. So im hoping tonight I can get my hands on one and really find out whats going on because I thought I had a bad MAF sensor and now that is not the case.

Thanks, mxdirtking

mxdirtking

So I was checking the relays and the power MAF relay was working but when I went to look at the burn off relay for the MAF it was like warm/hot and the others are not like that. So I found another relay just sitting around and hooked it up and started it but I had no luck.

ASE doc

To reset the ECM you simply disconnect the batt- cable for 30 seconds. You may very well have an open circuit in the MAF system. MAF sensor high generally means that the signal or ground circuit is open. Code 42 is another story. This means that the EST is either not switching to EST when commanded or that there is voltage on the EST return when in bypass mode. Is your timing connector(tan/blk wire) disconnected? If not you may have either a wiring issue, faulty ignition control module, or faulty ECM.

You really do need a scan tool. You also need a good repair manual and follow the diag sequence for codes 33 and 42. First reset the ECM and verify that the codes come back and/or that your engine performance issue is still there.

mxdirtking

Yeah I reset the ECM and got the codes back and started it up and the thing still did the same thing. Now is the tan/black wire the timing connector does that connect towards the top of the distributor where there are two seperate wires?

mxdirtking

I have a Painless Wiring Harness and I found that wire but it is with the group of wires that go the the plug in for the distributor I cant find that single wire. Hey ASE doc what do you mean by the signal or ground ciruit is open? Please help!

Thanks, mxdirtking

ASE doc

The timing connector is an inline connector in the tan/blk wire which is one of the wires to the 4 wire dist connector. Its should be in a breakout somewhere between the dist and the ECM. That is assuming painless did a thorough job of building the harness.

A sensor "voltage high" code generally indicates an open ground or signal circuit. The sensor circuit in the ECM contains a diagnostic resistor that supplies 5v to the signal circuit in the event that the signal or ground circuit is interrupted. We see this 5v diagnostic signal on ECM data when we disconnect a sensor. While sensor range is often stated as .5 to 5v, in actuality, sensor signal normally never exceeds 4.7v due to resistance in sensor circuitry. When the ECM sees 5v it sets a code and, for some sensors, goes into fault mode. This 5v diagnostic signal helps us differentiate between open circuits and shorted circuits. With a scan tool we can verify what is happening by watching ECM data. Otherwise, the best we can do is perform the diagnostic procedure for each code stored in the ECM.

ASE doc

I just caught on. You have the TPI out of an 85, not an 87. Yours has the internal coil HEI(large cap) doesnt it?. If so it doesnt have the single wire timing connector. Yours has a pigtail coming from the side of the dist body, below the cap. That pigtail goes to a 4 pin connector. On some early HEIs, you set timing by disconnecting that 4 pin connector. On fuel injected models, you have to place the ECM in diagnostic mode to set timing because the engine will not run with the 4 pin connector disconnected. Again, perform the diagnostic sequence for the code.

mxdirtking

Yeah it has the internal coil. And that makes sence now that you said that. I'll do that tomorrow and let you know thanks ASE doc!!! Im working on getting a scan tool but the guy is iffy letting me barrow his because he has $8000 into it and Autozone only rents out OBD2 scanners but people are saying as long as I have the codes I don't need a scan tool.

ASE doc

The benefit of OBDI is being able to read codes without a scan tool. A scan tool is still priceless though. Watching data can tell us alot when we're tracking down a problem. The FSM calls for us to check data with a scan tool for diagnosing some codes. I got by for years without my own scan tool, using my jumper to read codes and diagnosing codes with a test light and DVOM. Now, after years of using a scan tool, I feel crippled without it. You can buy an older scanner that will work great on your car for around $300.

mxdirtking

Okay got the timing light out put the ECM in bypass mode using a jumper because the Chilton said that you have to do that so I started it up and turned the dist. and the engine speed started to rise as I advanced the timing and the Chilton said that if that happenes that you need to disconnect the Set Timing connector but I have an internal coil so you have to disconnect the 4-wire connector to the dist. so I did and went to go start it up to check the timing and it wouldn't start inless you had that 4-wire connector in.

mxdirtking

Okay I just got done reading another tread and you have to remove the jumper before you start it so I think thats why it wouldn't start so ill try that tommorow not tonight its to late and I got wrestling in the morning. Hey ASE from your experience how can I fix that MAF (high) problem because getting my hands on a scan tool are slim but im still trying to get one but its killing me that I haven't drove my camaro in over a year with all the stuff ive been doing to it and then I run into stuff like this and its killing me!

ASE doc

The straightest path to a solution is usually the fastest. Complete the diagnostic sequence for the code(34). I think I already said that the FI motor will not run without the 4 pin connected. The ECM needs the crank referrence from the dist to fire injectors. The crank ref circuit is in the 4 pin connector. To set timing, you need to place the system in diagnotstic mode by installing a jumper between pins A&B of the ALDL. Engine RPM will increase some as you advance timing regardless of whether EST is active. Youll know when EST is bypassed because the timing will retard significantly and will advance only slightly with engine speed.

I just rechecked my service info. According to Mitchell, your car does have the timing connector. I get confused as GM made so many variants of the HEI system. I give up trying to remember which is which. Look for the single tan/blk wire with the timing connector in it. Should be close to the dist. If you dont find it, try as I said to put the engine in diag mode by installing the jumper. See if this allows you to set timing.

mxdirtking

Okat so I found that wire disconnected it started it up check the timming it look good. I shut the car off and reconnected the timing wire and reset the ECM went to go start the car back up and it wouldn't start. I sounds like it had no spark so I checked for spark and I had spark and the plugs are wet so I have no clue why it doesn't want to fire. Please help.

Thanks, mxdirtking

ASE doc

Oh man oh man oh man. Wet plugs generally mean either overfueling or no, or insufficient spark. Did you check spark on more than one plug? How is your state of tune?(plugs, wires cap and rotor in good shape?). Test KV using a cheap adjustable KV tester. You clamp it to a good engine ground, screw it out to 40K, then see if your spark will jump it. Test it first on one or two plug wires. If the spark wont jump the tester at 40K, test at the coil wire. If spark tests strong at the coil wire and weak at the plug wires, you need a tune up. If spark is weak at the coil, replace the coil and retest.

Overfueling takes us back to the CTS, MAF, TPS, or the cold start injector. Again, without a scanner you are limited in how well you can view information from the ECM regarding these sensors or the CSI. You can test the CSI by removing it from its port at the manifold, reconnecting the fuel line to it and checking it for spray when commanded on and for leaking when off.

The suddenness of your no start makes me really think you have an issue with state of tune. I advise you check this carefully. Perform the KV test as Ive advised. I think youre going to find a weak coil, and or a poorly performing secondary ignition system.

mxdirtking

My plug wires are new, my plugs are new but they have been sitting for awhile and my dist. rotor has not been replaced and it looks worn down. Its weird that after timing it, it just wouldn't start. I had it running just fine when I shut it off and then it took 5 seconds to reconnect the timing wire and then it wouldn't start after that. At first when I tried starting it after I reconnected the timing wire it was popping like it wanted to fire for a couple of seconds and then there was nothing it was just cranking over no popping or anything. I finally got a guy that will let me use his scan tool this week and so ill let you know about that too. Thanks ASE doc for all the help so far!

ASE doc

Thgis is an odd problem but sometimes thats how it goes. You may have just flooded it. Try starting it after its sat for a day. If it doesnt want to start, try holding the pedal down while cranking. If the new rotor looks worn down, you may have an issue with fitment of the cap/rotor. Check it carefully. With the scanner, look at CTS, TPS and MAF with key on and while cranking. Look for RPM to change while cranking if you dont get an RPM reading when crnking, you have an issue either with the ign module or the ppl/wht wire from the dist to the ECM.

mxdirtking

No the cap and rotor look like they have never been replaced and i doubt that they ever have. So tonight im going to AutoZone and ordering them and then I guess I have to wait till this weekend for that scanner.

ASE doc

Good plan. Let us know how it goes this weekend.

mxdirtking

Hey ASE doc I know that this thread is a little old but I got some more information for you. That weekend that I told you that I was going to get rotor and cap I did but the OBD I on the scanner that I was going to get doesnt work so im stuck without one. When I put the new rotor and cap on it fired right up but It still has that bog like delay when on the throttle. So I stored it in the shed for the winter but now I want get that problem fixed so I went to put new plugs in it because I thought that could be the problem because they have been sitting in there for so long and when I looked at the old plugs they were BLACK! So I figured it running really rich, so I showed some people the plugs and thet agreed that its just running rich and now I think that when I give it throttle it is just dumpping to much fuel in the motor. So I had a guy talking to me and he said do you have a vaccum leak and I told him I got them all pluged off and I know I don't have one. So then I explained to him that I dont have my VSS hooked up or my O2 senor and he said that is my problem. So for anyone out there or ASE doc is that my problem?????

Thanks mxdirtking

mxdirtking

Also Im still getting the codes 33(mass air flow(high)) and 42(electronic spark timing) and I double checked everything to do with the timing like rolled it over to TDC and took the cap off and it was all lined up and double checked the plug wires to.

mxdirtking

I was reading in my Painless manual and it was talking about getting ride of the VSS and it was to connect these two wires (blk/white) and (orange/blk) and it will eliminate the VSS so thats what I did so im thinking that it could be the O2 sensor not being hooked up. Any help would be great!!!

Thanks mxdirtking

mxdirtking

Any help would be awsome!

mxdirtking

I just installed an O2 sensor and when I drilled the hole for the O2 sensor i wasn't big enough and it made it go in crooked and when it went in it bent in those little vents but not bad I got to fix it all but I got it all in there and hooked it up and it still like missed when you hit the throttle but when I put it in the idle was different. It would idle high after I gave in gas and then it go really low like it was going to die.

ASE doc

How does the distributor itself look? Is it clean inside or corroded? How are the plug wires? The MAF code is likely your problem. Did you try running with the MAF unplugged? This will place the system in memcal default and it will run on a default fuel MAP. If everything else is okay, the engine should run reasonably well this way. If it doesn't then you need to look at fuel pressure, injector health, basic engine health.

The O2 is important. If it is shorted, it will cause the system to go rich. However, having it unplugged simply causes the system to stay in open loop. If everything else is okay, the engine should run fine in open loop. Follow the diagnostic flow chart for code 33. This should solve your trouble.