K4KAK

I just bought a 1990 Camaro RS. The old engine was removed and it was replaced with a 305HO and a 4 barrel Quadrajet. No computer control what so ever. Even the fuel pump is block mounted. The speedometer is electronic, not cable. It does not work at all. Is this due to the non-computer engine or is it due to something else. I have read all the post I can find on this topic and can not find a clear answer. Some say yes. Many say no there not connected. Others say this and that. In the end no one has fixed the problem or if they have I've not found it yet....Every other guage works perfect including the Tach. It has the BW 5 speed transmission. This is the only guage that does'nt work... I need some good help. Like I said I have read everything I can find. So looking for new information... Information that will fix this.... Thanks

Tuned Performance

iTrader: (92)

do you know if the t5 has a 2k or 4k vss, if it is 2k you need to use a vss buffer and and 4k optical out the the speedometer. If it is a 4k you will need to get a dakota digital sgi-5

K4KAK

I do not know which sensor is used. I would assume that the 2k would be gear driven and the 4k is not? Is the sensor on the tailshaft? If so, drivers side or passenger side.... I have been doing some more reading and I find different ones saying that the electronic is not controlled in any way by the computer. Right or wrong, I have not ideal..... I will look to see if it is gear driven or optical....Where if it had it, is the buffer box located and what does it look like? A picture would be good for reference.

Tuned Performance

iTrader: (92)

4k pulse per mile would be used on 90-92 tpi transmissions and lt1'a. the sensor is in the tail housing drivers side. the buffer can be in two places bye the pass side kick panel or behind the ip. the vss signal goes the the buffer and than to the ip. hopefully you have a 2k pulse per mile vss.

Tuned Performance

iTrader: (92)

90-92 tpi is controlled bye the ecm, if it was a tbi car the vss went to the buffer than to the speedometer.

vetteoz

iTrader: (13)

What engine did the car come with from factory? That determines how speedo was wired

K4KAK

Tunedperformace... what are you meaning when you use IP? Will the codes in the center console tell the engine? From the looks of all the plugs laying on top of the motor it was tpi if that helps....Lets say for discussion, the AC signal from the VSS is going to the buffer. Then what? The buffer is bad? Is there a way to test the speedometer to verify its ability to work?

K4KAK

Is there anyone in any of the post or threads who has repaired their speedometer? I to date have not found any one. Lots of advice but no clear answers.... I really need this to work....

Tuned Performance

iTrader: (92)

Ip Instrument panel, If you were unsure if this was a tbi or tpi car you could look at the 8th digit of your vin. Also if the harness is still there were the ecm was driver side under the dash if it was tpi there would be two black plugs and one yellow or green plugs for the ecm. If it was tbi it would have just two black plugs. If this was a tpi car the ecm has a internal buffer so you can get a 1227730 ecm and memcal out of a v6 and disconnect the check engine light and the ecm will send the 2k signal to the speedometer. If this was a tbi car you need to find the vss buffer on do some testing to see where the issue is. You can put the car on jack stands one you have located the vss signal purple and yellow wire going to the buffer and check for a ac signal.

K4KAK

Thanks Tunedperformance!!!! I think your going to be the one to fix my problem.. I let every one donw today because I blowed my low back out. I can NOT craw around on the ground... Maybe Sunday, I'll be better. I'm going to post my vin number to answer a question about original engine. VIN
1G1FP23EXLL125415 PLEASE DECODE THE VIN

K4KAK

I have found out the original engine was a type E, which is TBI... no ecm...vss straight to buffer

Tuned Performance

iTrader: (92)

Yes you are correct, the vin E was 5.0L tbi Lo3 and went straight to the buffer and branched off to the speedometer and too the ecm and cruise. No you just need to do the search to find it it was yanked out or not. I do have one but not the plug ends if you need one for fairly cheap.

Tuned Performance

iTrader: (92)

Sorry to hear about your back I know how spinal pain is , wouldn't wish it on anyone. Hope you feel better soon

K4KAK

I checked the vss and got 5vac from it. Its ok but the speedometer still doesnt work. Now hunting for buffer box. Is it under the drivers side or passenger side dash.....If I still measure the 5 vac going into the buffer, what readings should I get on the rest of the wires? Other than the 12v wire.

K4KAK

I have a big problem! My vin which is listed in the above post says my car had a tbi engine.... when you look at the wire loom under the hood you see a bunch of plugs that are all alike laying all over the intake.....Which tells me the engine was tpi and the vin was wrong.... see my problem! Looked under drivers side dash for buffer and it was not there.... only cruse control box and ecm..... What the crap do I do now and what route do I take?

K4KAK

for what its worth, the computer is still in the car and hooked up. The speedometer is the 145mph. 5 speed manual.

Tuned Performance

iTrader: (92)

um, thats odd does the ecm have a service number on it like 1227730 ? I will walk you through all the testing steps just need to know what the service number on the ecm is first. I would also provide a link after we continue and if the ecm is just going to be a buffer you might need to cut some of the leads so the ecm doesn't get shorted out. If might be as simple as the ecm not being powered up. If the buffer is there it would be on the passenger side bye the ecm or behind the instrument panel.

K4KAK

Thanks, There is no buffer. I will check to see if the ecm fuse in the fuse box is good. I'll get that number....

K4KAK

tunedperformance, I have checked the vss.. I get 1v ac to as much as I want depending how fast you spin it.... the computer fuse is good! If you watch the speedo needle closely when you turn the key on, you see a ever so slight move out of it...I can not get the ecm out because my body just wont let me get into that shape... but I have found the main wire harness going into the passenger side of the car to the ecm..... what is the wire coming out of the computer that goes to the speedo? If i knew that I could check it for any voltage when i spin the vss. That would rule out a bad speedo.
I have found a ecm pin out diagram at this address http://www.chevythunder.com/fuel%20i...ts.htm#1990-92 speed density f-body (ecm#1227730) ...check it to see if it is right... I can use it to verify a few things...

K4KAK

I see your online.... talk to me! tell me something else that is computer controled! What will tell me the computer is online and working a guage, a light, If the ecm absolute has to come out, maybe I can get some one younger to help me......

my ecm number is 1227730......

Tuned Performance

iTrader: (92)

sorry, I didn't see this post was updated. the input to the ecm is b9 and b10 the output to the speedometer is B11, The only other thing is still connected that would be computer controlled if the fans and ect is still hooked up to control them. Im not sure what output of the optical signal is.

Tuned Performance

iTrader: (92)

to see if the ecm is getting powered up, you might want to check and make sure the service engine light is installed and jumper the aldl pins a to b with the key in the accessory position. if the ecm is turned on the light will start the field service mode and will blink code 12 on the ses light. The aldl is the connector under the dash drivers side knee level.

K4KAK

I just fed 12v to B1 which was dead, the orange wire. I now have a check engine light and a relay click on the firewall. Drivers side corner. B11, speedometer wire, should have 12v but it only has 1.73v.. my question is this... Does the power to B11 come from the computer or the dash...So, I cut B11 and measured and I had 0 at the computer and 1.73 coming from the dash.... If 12v is to come to the computer from the dash, I have a dash cluster issue.. If 12 volts comes from the computer, I have a computer issue. Comments?

K4KAK

While no one was online I done some trouble shooting. B11 which either comes to or goes from the computer is supposed to have 12v. Mine has 1.73. I cut B11 and the 1.73 was coming from the dash cluster. Not the computer. B11 from the computer was 0v. I removed the dash cluster and removed the plug on the passenger side, (plug C1) which controls the tach and other things. I only plug in C2 which has a 12v gauge power which is the pink and black.... Remeasured B11 at the Computer and still had 1.73. That tell me the 12v which the computer pinout shows comes from the insturment panel and not the computer.... If I am incorrect about this, please tell how im wrong and why.... Thanks.....

K4KAK

I have brought in my dash cluster. Inside the speedometer section there is a small circuit board. The first connection on the board is B11 brown, and pink and black which is Guage power.... interesting..... may need this board....

Tuned Performance

iTrader: (92)

b11 is the output from the ecm to the speedometer c2 number 1, Im not sure what wave form this is I think more of a squared. the output should very off of the input vss speed. I asked rbob to help chime in.

K4KAK

I have 1.73v from the cluster. Nothing from the ecm.. I cut B11 and took measurments: ecm 0v. Cluster 1.73....The 1.73 volt is coming from the pink and black 12v guage power wire via the small electronic board in side the speedometer

Here is something I noticed while trouble shooting. While I had the B11 wire cut, I could touch the lead which went to the speedo and the speedometer would jump. The faster I touched it, the higher it would read. Looked like it was trying to work.

K4KAK

I checked my vss. I chucked it in a drill and it will read any thing between 1v ac to 20v ac... voltage is speed dependent

Tuned Performance

iTrader: (92)

I just looked at a service manual, the information I got from austin 3rd gen is incorrect according to the schematic. It shows b11 a brown wire going through c207 changing color to gray and ending up at c8 c2, page 8a-33-0 or gm's 90 camaro service manual.

Tuned Performance

iTrader: (92)

the service manual states the vss signal depending on speed the input side is from 1-5v so your good there. The signal from b11 is from less than 1v to4v with the key on and the car on stands in drive. if that is within the range you have a speedometer issue.

K4KAK

your right~ B11 is brown when it leaves the ecm and then it turns to grey at the cluster. I noticed this a bit ago.... I checked with an ohm meter and they are the same wire.....
some where they just changed color....

Tuned Performance

iTrader: (92)

it changed color at c207

K4KAK

I have 1.73 volts dc regardless of how fast you spin the vss. I hooked up two meters. One on the vss and one on the B11. vss would go from 1 to 15 or 20. speed dependent. the 1.73 never changed

K4KAK

did your source say which way the B11 power was coming from? Like I said, When I cut B11 I had 1.73 coming from the cluster and 0 from the ecm

K4KAK

I want to say thanks for all your help up to this point. I hope we can fix this thing..... I believe I understand what ever you ask so dont hesitate to make a suggestion...

Tuned Performance

iTrader: (92)

B11 is the ecm's output for the vss signal to the speedometer when the vss is sending voltage to the ecm this is the buffer output. If it wasn't sending out less that 1 to 4v I would check the ecm grounds behind the passenger cylinder head first. The c1 on the 1227730 is the middle black plug ecm connector. the b11 is next too the yellow vss input wire.

K4KAK

you are right! B11 is next to the purple and yellow vss wires. I did check all black with white stripe wires for ground and all checked ok.... C1. Are you referring to c1 on the ecm which is the cruise control red wire 2000 ppm. I will check behind the passenger side head for a ground....

Tuned Performance

iTrader: (92)

sorry I put c1 is the connector number 1 in the 1227730 ecm although its in the middle go figure.

http://tpiparts.net/1227730_pinout_diagram

Tuned Performance

iTrader: (92)

but speaking of that is c1 on the ecm putting out anything when you have the key on and spin the vss?

articwhiteZ

iTrader: (56)

one more thing to check, that alot of guys forget. take the VSS out of the tranny (1, 10mm bolt?) and look at the gears. both, on the shaft and the VSS. make shure. they are not ground down, (have seen that before)

if so it's a simple fix

K4KAK

I dont know, give me one second and I'll check....... be back.

K4KAK

great thought, but the gear is like new.... thanks.....

K4KAK

no, nothing to the c1 red wire to cruise control module

Tuned Performance

iTrader: (92)

with the vss turning and nothing out at b11 or c1 sounds like a bad ecm. Not sure how you get a reading at the speedometer it self. did you ever see if the ecm is going into diagnostic would save you from testing the power and grounds.

K4KAK

Here is a funny thing, I accidently touched the speedo needle and knocked it off Zero. It went to about 60. when i turned on the ignition, the speedo reset its self to zero. it may not register, but it will reset......

K4KAK

before I buy a ecm, I want to know if there is a way to properly test the speedo to make sure its not bad. To replace it would be 300 + dollars, so before I throw around that kind of money in the wind, I would like to know if there is a need...... Is there any sure way to know?

1992COUPE

K4KAK If you need a ecm, a reman from gm is $117.45 plus tax with a core ontop of that of $81.00. I can get one anytime you need it. So when core is returned it would be $126.38 plus shipping.

RBob

iTrader: (1)

Does the SES light blink of at key-on, engine-off? Can you blink codes out? If not then likely there isn't a MEMCAL in the ECM. Which can prevent the VSS outputs from working.

As for no power on B1, they likely pulled the 20A under hood fuse.

The speedometer provides the voltage to the ECM for the pulse stream. It should be the current vehicle voltage. But since you can get the speedometer to move by touching that wire (to ground?), I would work on the ECM end first. If the ECM is bad, can always wire in a 4-out buffer.

To check the ECM pulse stream output, use a resistor in the 4.7K to 6.2K range to that ECM pin (B11, B12, or C1), and the other end of the resistor to +12 volts (vehicle voltage). With no motion that will pull up the ECM output to vehicle voltage. With motion on the VSS most DVMs will show about half the vehicle voltage.

Being a VIN E car someone likely did the TPI swap.

RBob.

K4KAK

Does the SES light blink of at key-on, engine-off? YES......


Can you blink codes out? YES,....

If not then likely there isn't a MEMCAL in the ECM. Which can prevent the VSS outputs from working.

As for no power on B1, they likely pulled the 20A under hood fuse.... Dont know where that is, but I will research.....


The speedometer provides the voltage to the ECM for the pulse stream....I HAVE 1.73 VOLTS DC CONSTANT.. IT DOES NOT VARY WITH VSS SPEED...


It should be the current vehicle voltage. ITS 1.73 VOLTS


But since you can get the speedometer to move by touching that wire (to ground?), NOT TO GROUND, WHILE I HAD THE WIRE CUT, THE SPEEDO WOULD MOVE BY TOUCHING MY VOLT METER PROBE TO THE WIRE... FASTER I TOUCHED, HIGHER IT WOULD GO....


I would work on the ECM end first. If the ECM is bad, can always wire in a 4-out buffer.... GOOD NEW THERE BUT DONT HAVE 4 OUT BUFFER.....



To check the ECM pulse stream output, use a resistor in the 4.7K to 6.2K range to that ECM pin (B11, B12, or C1), and the other end of the resistor to +12 volts (vehicle voltage). With no motion that will pull up the ECM output to vehicle voltage. With motion on the VSS most DVMs will show about half the vehicle voltage.....WHAT WILL THIS TEST PROVE?

Being a VIN E car someone likely did the TPI swap....I HAVE NO IDEAL..

RBob.[/quote]

Tuned Performance

iTrader: (92)

Thanks for the advice to help him rbob