After having the engine replaced due to throwing.

Tiny
BKO1
  • MEMBER
  • 1993 TOYOTA CAMRY
  • 206,000 MILES
After having the engine replaced due to throwing a rod, the tachometer now reads zero when cold and about 250 rpm low after warming up. I've checked all the fuses and swapped out the ignitor since the schematic shows the ignitor supplying the signal. I've looked at all the engine harness wiring and can not find any discrepencies, the next thing may be to get the meter out and ring out all the wiring. The schematics I'm using are from the Haynes manual so I'm not sure they are entirely accurate. Where does the tach signal come from and where should I look next?
Sunday, October 21st, 2012 AT 1:55 AM

7 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
It sounds like the tach in the cluster

Roy
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Sunday, October 21st, 2012 AT 2:01 AM
Tiny
BKO1
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That would be the first thought, however I've read about three people on another Toyota forum that had the same problem and replaced the tach to no avail. It sounds like a wiring problem, but one of the other people had it happen and there was no maintenance or part replacements done prior to it happening. There appears to be a surge suppressing capacitor on the ignitor/coil assembly and I'm wondering if that capacitor were to go bad would it cause this type of problem.
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Sunday, October 21st, 2012 AT 5:43 AM
Tiny
KHLOW2008
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Check the grounding circuit at the intake manifolds.
Ensure ignition coil + and - wires are not interchanged.
Which engine do you have? Manual or AT transmission?
Same engine replaced?
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Sunday, October 21st, 2012 AT 6:02 AM
Tiny
BKO1
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Yes the same V6 engine was installed, it was out of a '93 Lexus, it is an automatic transmission. The coil wires cannot be interchanged since they are a keyed plug. All the grounds on the engine were tight.
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Tuesday, October 23rd, 2012 AT 4:34 AM
Tiny
KHLOW2008
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At the check connector terminal # 19 (Black wire) atttach a tachometer and test if it works.
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Tuesday, October 23rd, 2012 AT 6:14 PM
Tiny
BKO1
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Which check connector? The one under the hood and the diagnostic connector under the dash are not numbered.
The grounds were all good and tight.
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Wednesday, October 24th, 2012 AT 4:23 AM
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
The one underhood. Sorry I could not find any identification diagrms to show you. If you check from rear of DLC, you should see a black wire.

Alternatively you can start from igniter. Terminal # 4, Black wire.
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Wednesday, October 24th, 2012 AT 12:19 PM

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