E420 throttle issue - Engine speed signal

[alx201020]

93 E420. throttle body was not working. Idle was 1200-1500. Limp mode. I changed idle speed control [E-GAS] module. Now throttle is making noise. Working.

But when I start engine, after 2-3 seconds it stops working and again 1200-1500..... Star diagnose show only one trouble code. 160 Engine speed signal TNA from GM N16/1.

Throttle body I changed. no difference.
LH changed .No difference.
GM changed. No difference.
EZL changed . No difference too....

Magnets on the flywheel are on there places. I dont know what to change more...

 

[gsxr]

I assume this has already been taken care of, and it may not cause the problem you are seeing, but has the upper engine harness been replaced with the improved insulation?

Curious if @Alphasud40 has any ideas on this one.

From the diagnostic manual here... not much help for code #160 /

STAR TekInfo

 

[alx201020]

Harness is good.

 

[gsxr]

Was any work performed just prior to the problem appearing, or did the fault occur suddenly?

Is the rear crank sensor OE/OEM?

Are the module part numbers (E-GAS, LH, ASR, EZL etc) all correct for 124.034 chassis?

 

[Alphasud40]

I concur with GSXR I would perform that circuit check as well. Modern diagnostic practice is to unplug both modules and test the circuit under load with a test light by either grounding one pin and checking with a test light connected to B+. Also make sure pin tension is good. Not so much an issue on older vehicles provided somebody didn’t damage the terminals but still it’s good to check. Also make sure the connector is fully seating into the module. Had one where the connector on the box deflected enough for the pins to be not fully seated causing an intermittent issue.

 

[alx201020]

Man bought this car with this problem. I dont know what sensor is there, but another one is in the trunk. I think they changed it before. Do you think sensor may cause this problem?

 

[Alphasud40]

Without looking at the car it’s hard to say. If it’s aftermarket I would be suspicious. However if this sensor didn’t work the car probably wouldn’t start and run. Plus no codes on the EZL for a sensor issue.

 

[gsxr]

Agreed, if there's no error code on the EZL in HHT-Win, it seems unlikely this is the problem. However, I would try a different sensor if available.

Check the connector at the EZL, the connector should show a part number and/or brand name. If the connector back surface is "blank" with no numbers or names, it's aftermarket. OEM's are Bosch and AB-Elektronik. More info here.

See waveforms expected in this post:

FYI - OE / OEM crankshaft position sensor (CKP) review | M119 Engine

Received my "OEM Supplier" CKP today from AHAZ. It's Hella, made in Spain, identical to what RME is selling. Both are ~$70. If anyone buys from FCP, please report what you receive. If they are selling a different/better item for $100, it would be nice to know...

www.500eboard.co

 

[alx201020]

All the harness is original. There is Delphi badge on the harness .

 

[gsxr]

If the FD date on the harness is late 1990's or newer, it's the updated style and is good.

 

[alx201020]

The car is 93 E420

 

[gsxr]

The car is 93 E420

Yes, and the original harness will be 1993 or older.

If the harness has been replaced, the FD datecode should be (approximately) 1997 or newer. Many cars already had the harness replaced in the past, they were common failures.

 

[alx201020]

No, it is original 1993.

 

[gsxr]

No, it is original 1993.

Ohhhhh. You should see degraded insulation at the wires, where the insulation flakes off. See sample photos below. More photos here.

I don't think this will cause the problem you are experiencing, however it would be good to replace the harness before further troubleshooting. EPC shows p/n A1244401906 for all Euro-spec 034's. Still available new, $560 USD list, $400 USD discount in USA. Might be €500-700 in Europe with VAT depending where you buy it.

 

[alx201020]

No problems with insulation. I restore cars, Mercedes benz especially. I know about this problem. This harness is without any problem.

 

[alx201020]

I assume this has already been taken care of, and it may not cause the problem you are seeing, but has the upper engine harness been replaced with the improved insulation?

Curious if @Alphasud40 has any ideas on this one.

From the diagnostic manual here... not much help for code #160 /

STAR TekInfo

View attachment 208715

View attachment 208714

Hello again. I dont understand what it mean. What is 78 , 75 . what is 1.37 and 1.34

 

[gsxr]

Hello again. I dont understand what it mean. What is 78 , 75 . what is 1.37 and 1.34

78 and 75 are pin numbers from the breakout box, which you won't have. It's showing to measure DC voltage (+ lead to 75, - lead to 78).

I'm not quite sure what 1.34 / 1.37 indicate.

Connection info is here: STAR TekInfo