Can I use a old style dwell rpm meter to check the rpm. Where do I hook up the wire that I would hook up to the tach. lead on a old HEI dist . I have a 88 Chevy and don't see a place to hook it up. Also the engine seems to idle to high. No trouble codes show up and the check engine light has not come on. Does this mean everything is OK.

 

Green tach wire should come off the harness about 4" before it conects to the distributer modual (at the base of the distrubuter cap)

 

use the search for a high idle because this was a topic recently. Many things cause it, IAC ... Vacuum leak, stick throttle ....

 

I found the tach lead all taped up and hidden. Thanks. While I am looking through all the high idle posts here is whats happening. After it is all warmed up it does not drop below 950 rpm in drive or 1500 in park. No trouble codes are stored in the computer. Where should I begin? It Also revs very high, near 2000rpm on initial start up when cold.

 

timing or your IAC valve . .try checking your timing first.

 

I checked the timing and IAC. Both seemed OK. Then I started looking more closely for a vacuum leak. Finally I found a leak in the TBI mounting gasket to intake manifold, in back of course where it is very difficult to check. Thanks for everybodys help.