Guye
Lifer
I see your point...how do I test the theory though. Any ideas?
At my wits end
- Thread starter Guye
- Start date
Guye
Lifer
Rpm signal from the distributor...the plot thickens. I also "borrowed" a working distributor and swapped with mine, it gave the same results as mine. I think I need to research the tach issue and see what I can come up with. There must be info on where the signal comes from, the voltage etc. I can then use a multimeter and check the wires and see what's going on.
Dave.
Member +
Would be fairly easy - if you're speed truely hasn't changed (test it like i said earlier - alongside another car at any speed you mentioned
If the car you're beside says the same speed (if you can't get a GPS that is) then you know its the tacho
- you couldn't possibly get the same speeds with the same gearbox at less rpm Dave
Guye
Lifer
I suspected the timing as well. It was checked and it was spot on.
EDIT:
I just remembered that the slots on the crankshaft pulley was filed out by the mechanic for some strange reason and it was difficult to see the mark with the timing light...It looked right...I think I will replace the pulley and try again and see if it is out or not.
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weeJohn
Lifer
Your description of what happens at 6k revs sounds like the rev limiter being hit. Another thing that points to a mis reading tacho. You said you only took it there once before, maybe because you didnt hit it before it is unfamiliar to you.
The tacho is fed from a pulse coming from one of the 5 wires coming from the ignitor. I think it is IG- and it also goes to the diagnostics connector.
i dont know how to check the signal is correct, especially with a multimeter, but you could check the cables for damage, and also that there is continuity to the tacho at the instrument cluster.
It sounds like your "mechanic" may have caused this, as there is no other explanation.
Have you tried fitting another instrument cluster to check if the tacho is reading the same??
The tacho is fed from a pulse coming from one of the 5 wires coming from the ignitor. I think it is IG- and it also goes to the diagnostics connector.
i dont know how to check the signal is correct, especially with a multimeter, but you could check the cables for damage, and also that there is continuity to the tacho at the instrument cluster.
It sounds like your "mechanic" may have caused this, as there is no other explanation.
Have you tried fitting another instrument cluster to check if the tacho is reading the same??
Guye
Lifer
UPDATE: I took the car and had the rpms checked with a multimeter. The mechanic used a clip similar to one found on a timing light that plugs into the meter. According to the readout my car is reving to and limiting @ 8000rpm! On idle the meter reads approx. 985rpm with a/c on while the tach gauge in the car shows about 500rpm. This is one problem solved. The culprit is the tach gauge giving a false reading causing me to rev the engine at a stupid level and limiting. I am very confident the slight hesitation before what I believed to be 3000rpm mark will be due to the timing being slightly out.
The question now is, how do I recalibrate the tach gauge so it shows the correct engine rpm? Do I simply replace the entire gauge cluster? Any ideas are welcomed & thanks for the inputs so far.
and limiting. I am very confident the slight hesitation before what I believed to be 3000rpm mark will be due to the timing being slightly out.The question now is, how do I recalibrate the tach gauge so it shows the correct engine rpm? Do I simply replace the entire gauge cluster? Any ideas are welcomed & thanks for the inputs so far.
weeJohn
Lifer
I would try another cluster on your wiring mate to see if its the cluster or the loom. You need a local mate with the same car as you.
I dont know if you can recalibrate or adjust the stock tacho. People always say they are slightly inaccurate, but from what you have said, it does not seem anything has been done to the tacho to knock it off.
It all still points to this mechanic doing something to make this happen. Try the different clocks, if it is them, it may be just bad luck that they failed at that time. If its not the clocks, the mechanic is responsible for the bill for repairing it.
I dont know if you can recalibrate or adjust the stock tacho. People always say they are slightly inaccurate, but from what you have said, it does not seem anything has been done to the tacho to knock it off.
It all still points to this mechanic doing something to make this happen. Try the different clocks, if it is them, it may be just bad luck that they failed at that time. If its not the clocks, the mechanic is responsible for the bill for repairing it.
Adam_Glanza
Member +
i was gonna say does the revs just get to 6000 and then redline or does it keep continuing slightly till redline?
it sounds like the tacho is just bust and making you think its only revving that hard.
but if you keep pushing it i bet it doesnt actually hit the limiter at 6000.
it sounds like the tacho is just bust and making you think its only revving that hard.
but if you keep pushing it i bet it doesnt actually hit the limiter at 6000.
Guye
Lifer
It does feels like it hits a limiter at 6000rpm. It also stops at 6000rpm on the tach. The multimeter reading shows that the engine is actually revving to 8000rpm although it's only showing the 6000rpm on the tach. I guess I will have to get gauge cluster then...I was kinda hoping I could fix the one that's in there now.