Working out some kinks UPDATE (Bogging, jerking, hesitating at low ks)

[Jib05]

ok guys ive been searching the forums for a reason why my car bogs under load and rev limit is very low. So i have found that a speed signal needs to be wired from the DME to the dash.

Speed signal is now connecting and functioning.

UPDATED

But i still get bogging, jerking, hesitating at low engine speeds and my idle is absolutely shit. idles at 500rpm but is around 16:1 AFR and i have to keep pulsing the gas to keep the engine alive. I'm still scouring the internet for information.

So far i've

- changed injectors
- changed DME
- checked TPS
- changed MAF
- changed FPR
- cleaned ICV

Still on the to do list is fuel filter and fuel pump. Could the idle control valve cause a vacuum leak and cause it to idle/drive rough?

Also another question is my particular E30 came with one fuel pump. Not an intank one but under the car. Which seemed weird because I was under the impression that there were two? I've checked where the intank pump is SUPPOSED to be but there is only a fuel level sender and no provisions for another fuel pump (lift type). Hmm this sure is confusing.

[Navarone]

Working out some kinks (speed signal)

Correct. And the wire starts here.


If you've taken your cluster out you've probably knocked it out and didn't notice. I did the first few times.

[Jib05]

Thanks for clearing that up! But what happens if I don't have a speed signal in my cluster or my c101? I just had a good look at my harness and it has no wires going to pin14c101 but has the black and white wire at pin14x20.

back of cluster


*did some reading and to wire it to c3pin26 at the back of the cluster. Another issue which i am facing is a don't have any wires nor yellow female plug to connect.

Seems like I have bigger kink than I initially expected

[Navarone]

Working out some kinks (speed signal)

Do you have the 13 button computer? That's what the yellow plug is for. Is there a place to plug that green plastic thing with the circuit board into? See th pic up there with a little bit of the yellow plug on the left side, that should help locate it. Is there a stray wire hanging in the dash somewhere that will plug into the green thing? I think mine came off the blue connector bundle and was about a foot long extra, but not sure, and mine is an 85 so it's different. You might have a car with an early build date, or the cluster was fiddled with or swapped.

I'm not home, so I'll have to look at the manual later to know what all the plug and harness numbers are.

[Jib05]

Hey mate, I just had another look at my cluster wiring. I dont have any other plugs or wires coming off the C1 or C2 plugs. My car didnt come with a 13button obc either or wiring for the yellow plug(C3). Ive read a thread where they have spliced into the C2 plug and had gotten the signal straight from the speedo. But im not sure if that would be wise (or possible).

I had a look at the cluster itself as well. I see where the green plug would go if it were there. I then looked at the speedo itself and it does look like there are points to get a signal.

Can anyone verify these points?

see the two points were a plug could be used


Where the green plug would usually

[Navarone]

Does the cruise control work? The bogging could be a few problems like vacuum leaks, low compression, clogged injectors, it's really annoying to track down.

[Jib05]

My e30 is poverty spec. No ac, no Cruise control, no power windows, no ABS. Euro poverty spec haha.

I did another hunt for vacuum leaks last night. Couldn't locate any. I don't think the injectors are clogged because my wide-band tells me i'm full rich when it starts bogging down, but it could be the ecu trying to compensate for something...

I have purchased a fuel filter anyway (I haven't changed it in my ownership of the car).

Thanks Navarone for taking the time to reply btw.

[Jib05]

Bump

[dsm2002]

I tried to map the C1 and C2 pins and have this far. It seems that C2 pin 12 has the speed signal.

[Feedback on this mappaing is welcome]

[pandaboo911]

Working out some kinks (speed signal)

The picture of the 2 pins you mentioned is for the green plug.

The pins should be marked"A" and "31"

A is the speed signal output, aka VSS. This goes to pin 14 x20 which is the black/white wire that runs to pin 42 at the DME.

31 is ground. Don't need to do anything with that

Grab a green plug from a junkyard cluster, plug it in, and use any of the 3 pins provisioned for the speed signal.

I had the same bogging. Hook up VSS and reset the ECU by disconnecting the battery for 10 seconds. Also check your fuel pressure. Low fuel pressure can bog the engine and prevent it from revving past 5k

[Jib05]

I tried to map the C1 and C2 pins and have this far. It seems that C2 pin 12 has the speed signal.

[Feedback on this mappaing is welcome]

That's pretty cool that you are doing that! I found a few threads/wiring diagrams that say pin 12 is the speed signal, but the colors don't match my wiring so i'm hesitant to splice the wire on to it. I think i am blind or cant read, where does pin 1 start from on the c2 plug? lol

The picture of the 2 pins you mentioned is for the green plug.

The pins should be marked"A" and "31"

A is the speed signal output, aka VSS. This goes to pin 14 x20 which is the black/white wire that runs to pin 42 at the DME.

31 is ground. Don't need to do anything with that

Grab a green plug from a junkyard cluster, plug it in, and use any of the 3 pins provisioned for the speed signal.

I had the same bogging. Hook up VSS and reset the ECU by disconnecting the battery for 10 seconds. Also check your fuel pressure. Low fuel pressure can bog the engine and prevent it from revving past 5k

Wow cool mate thanks for the advice! I wish it was as easy as that to find a green plug! Junkyards here hardly have any BMWs other than 318/ti e36s. My local wrecker is trying to sell me one for $100.

That's very true about fuel pressure, ill be investing in brand new fuel pumps soon. Also wanting to put a fuel pressure gauge on the line from under the intake manifold to the injector rail, in front of the engine, just above the oil filter (if you know what i mean).

thanks for the help guys!

[pandaboo911]

That's pretty cool that you are doing that! I found a few threads/wiring diagrams that say pin 12 is the speed signal, but the colors don't match my wiring so i'm hesitant to splice the wire on to it. I think i am blind or cant read, where does pin 1 start from on the c2 plug? lol







Wow cool mate thanks for the advice! I wish it was as easy as that to find a green plug! Junkyards here hardly have any BMWs other than 318/ti e36s. My local wrecker is trying to sell me one for $100.



That's very true about fuel pressure, ill be investing in brand new fuel pumps soon. Also wanting to put a fuel pressure gauge on the line from under the intake manifold to the injector rail, in front of the engine, just above the oil filter (if you know what i mean).



thanks for the help guys!

http://pages.ebay.com/link/?nav=item.view&alt=web&id=171674633961

[Navarone]

Working out some kinks (speed signal)

Before you go buying random shit, it doesn't look like your cluster had the right pins to make this work. See the two pins next to each other, those seem to match up, but the third one on the left doesn't have a spot in your cluster to plug in to. Can someone confirm that this will plug in and work? Maybe the green plug is offset a few pins and will work fine, I don't know :/

EDIT: Upon further inspection it looks like the gauge is offset. See how the mounting screws line up with the center of the green plug? I think it'll work, but make sure before you go buying stuff.

[pandaboo911]

My speedo has the same 2 pins and it has a green plug. The plug is universal. I think some cars didn't have it because they didn't come with cruise control.

The later model speedos have 3 pins on bottom but the plug is the same.

[Jib05]

Thanks for all the feedback! I did have that one saved on my ebay acc. But thankfully i have found someone locally that will post me one for a very good price. I will double check when the plug arrives that it can actually fit. Will update this when it arrives.