I've tooled around the archives for about 2 days and was not able to find information that I'm looking for. I'd like to connect an obd2 to my swap (1998 3800 s/c in a 1986 GT with 5 speed) so I am able to connect my obd2 diagnostic tool. Is there a diagram or pinout for this?
Very simple for the OBD II connector pin 2 goes to PCM usually pin 59 of C1, pins 4 and 5 are ground and pin 16 is battery + 12 volts constant. the tan wire from PCM C1 pin 15 is not needed and any other wires on the connector can be removed. Dan
Thank you so much, Dan! I got my connector from a junkyard this morning, swapped the pins to the correct positions and will wire it up when I get home from work. Thanks again!
Worked great and I got my code. P0452 - Fuel Tank Pessure Sensor Circuit Low Voltage. After looking around a bit I have come to the conclusion that I should not be getting this code at all. I did not have my PCM reprogrammed because I was under the impression that I did not need it done with the 5 speed tranny. Am I correct in those two conclusions?
I'm looking into my vacuum system to see if I can find a solution to my problem. I'm getting diagnostic P0452 - Fuel Tank Pessure Sensor Circuit Low Voltage. My engine runs and idles fine. The issue is that when I get on the throttle, there is hesitation to accelerate. It stutters or stumbles, those are the two words I can use to describe it. Is there anything wrong with how I have my vacuum lines connected? My other question would be concerning the evap switch (if you notice on my diagram, it is not connected to anything. I don't know where it is or what it looks like). Is that located on top of the fiero's evap canister? If not, where is it located?
The image below is what how I currently have my vacuum connected.
The image below is what I have been using as my guides (both of which I found here on Pennock's, not mine)
Did you add an FTP sensor when you swapped the engine? The Fiero doesn't have one stock.
The newer pcms use it to monitor evaporative emissions system functionality. Normally it'll be a small three wire sensor attached to the top of the fuel pump module.
I was under the impression that with a manual trans that I wouldn't need a pcm tune. Am I wrong? It worked perfectly in the 88 fiero my setup came out of.
Nope - Did you look at a dirty MAF for your studder issue?
The MAF measures air flow. it does this by measuring how much current is needed to pass through a wire to keep it at a constant temperature. Using a over oiled foam filter or even just over time the MAF wires can get coated with crud. That crud insulates the wires. So when you pop the throttle open the insulated wire doesn't read the quickly changing air flow. The PCM doesn't inject the correct amount of fuel right away and a hesitation is the result.
Sprayed the MAF sensor pretty good with the MAF cleaner. No change Bought a fuel pressure gauge from harbor freight. I'm getting about 40 psi with the key on, but engine off. I get about 45 at idle and 50+ at rev, so that seems to be close to within spec. What else should I look for?
I'm not sure what drugs Scotty Kilmer is on, but I want to make sure I don't ever do them.
So it could still be a bad MAF, it might have been nice to grab one from the junk yard if you had the chance, just for testing.
Did the 3800 always do this or is it something that just started?
Does the engine miss when it hesitates or just a hesitation?
You have a good connection to the MAP sensor, no kinks or other obstructions correct?
Plugs look good?
GM changed the MAF between 98 & 99. An -04 MAF is 96-98. An -05 MAF is 99+ Your PCM needs to be programmed correctly for your MAF. So if your MAF is 98 or earlyer it needs to be mated with a PCM programmed as such and vice versa. If you look at the MAF in my picture above you can see it is an -04 MAF
Disconnect and plug the hoses to your BBV and see if the trouble stays the same.
[This message has been edited by phonedawgz (edited 11-11-2013).]
With a manual tranny swap with the 3800 engine you need the PCM programmed to match for more then just the check engine light. the IAC code has to be altered for it to idle properly or even half decent wise and not want to stall most of the time on deceleration or idle. Dan
Did the 3800 always do this or is it something that just started?
Here is the background on my setup. My father put this motor in his 88 GT 5 speed back around 2002-2003. Everything ran great with no issues and always put a smile on our faces. However, he couldn't get it registered in CA, so we decided to put it in my 86 GT 5 speed. Back then we experienced the exact same issue. We cut our losses and put the 2.8 back in so I would have something to drive for the little while before I left the country for a bit. The motor sat in his car's cradle from then until last year. I got it back from him and put it in my car and I have the same issue. So the engine has never run correctly in my car, but ran like a champ in my father's car.
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You have a good connection to the MAP sensor, no kinks or other obstructions correct?
Are you referring to vacuum line, electrical connector, or both? I checked the vacuum the other day with my finger gauge and there is vacuum.
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GM changed the MAF between 98 & 99. An -04 MAF is 96-98. An -05 MAF is 99+ Your PCM needs to be programmed correctly for your MAF. So if your MAF is 98 or earlyer it needs to be mated with a PCM programmed as such and vice versa. If you look at the MAF in my picture above you can see it is an -04 MAF
It is a-04 MAF on a 98 PCM.
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Does the engine miss when it hesitates or just a hesitation? Disconnect and plug the hoses to your BBV and see if the trouble stays the same.
It feels like its missing. I'll try to get a video of it so you can have a better idea. I'll disconnect the BBV, probably tomorrow, and see what that produces.
I got a used MAF in the mail from eBay, installed it and am having the exact same problem. However, while under the decklid today, I found some things that I have questions about. Hopefully I can get this figured out, as I have to renew registration this month. Here goes...
Question 1: What, if anything, gets connected here? The other side is connected to the back of the air filter box.
Question 2: Where does this line, that I have traced in red, connect to on the other end (to the right)? Also, what is that under the air filter box?
Question 3: What should the MAF reading be at idle? I'm getting about 35 cfm at 785 RPM, and 177 cfm at 3625 RPM.
Question 4: What should vacuum pressure be at idle? I'm getting 23 in/Hg (11.3 psi) at 741 RPM.
I did some continuity checks on the MAF today. I found something that seems a little weird to me, so I'm gonna ask here and hopefully someone can tell me if its normal or not.
C1 and C2 are disconnected from the PCM, along with C203. Pin 19 should be ignition Positive Voltage (hot in run) and connect to F of C203. I metered from pin 19 on C1 (pink wire) to C+ on the MAF (pink wire) and got continuity, seems normal. The part that I'm wondering about is that I also got continuity with ground. Is this wrong?
I did some continuity checks on the MAF today. I found something that seems a little weird to me, so I'm gonna ask here and hopefully someone can tell me if its normal or not.
C1 and C2 are disconnected from the PCM, along with C203. Pin 19 should be ignition Positive Voltage (hot in run) and connect to F of C203. I metered from pin 19 on C1 (pink wire) to C+ on the MAF (pink wire) and got continuity, seems normal. The part that I'm wondering about is that I also got continuity with ground. Is this wrong?
Should be ok because you are reading the maf resistance to ground. You should try adding a few extra grounds from your engine to frame. I know I seen some info about that here.
[This message has been edited by TbirdMarc (edited 01-15-2014).]
Bought a fuel pressure gauge from harbor freight. I'm getting about 40 psi with the key on, but engine off. I get about 45 at idle and 50+ at rev, so that seems to be close to within spec. What else should I look for?
