Hoping someone here can help me out with a rough running '87 Ford 460 with a 4V Holley on it.
Here's the deal - runs rough and very rich. Have spark at all 8 plugs as tested with a timing light. Can't get to all the plugs easily but of the four I can get to - the compression is good - averages 140 psi on each cylinder with no major adjacent differences.
On the left side of the engine, testing with an infrared tester, the EGTs are about 400 degrees at each exhaust port, however, on the right side only cylinder 4 has a 400 degree EGT - cylinders 3 (which has a 140 psi compression) and cylinder 2 (can't really reach 1) have an EGT of only 200 degrees. A 200 degree EGT difference just screams somethings wrong - but I can't find the problem.
There's one of those early EGR systems under the Holley but there's no real way to test it - and I don't think it would only affect cylinders 1, 2 and 3 (which are all adjacent on the right side). Is it possible that the Holley is built such that half of it supports cylinders 1, 2, 3 and 4 while the other side supports cylinders 5, 6, 7 and 8? By the way - don't know at this point exactly which Holley model is installed.
So - to summarize - have a very rich poor running 460 with no obvious problems, and 3 of the 4 cylinders on the right are running EGTs 200 degrees less than the 4 cylinders on the left side.
I'm stumped and open to any suggestions. Thanks in advance.
Here's the deal - runs rough and very rich. Have spark at all 8 plugs as tested with a timing light. Can't get to all the plugs easily but of the four I can get to - the compression is good - averages 140 psi on each cylinder with no major adjacent differences.
On the left side of the engine, testing with an infrared tester, the EGTs are about 400 degrees at each exhaust port, however, on the right side only cylinder 4 has a 400 degree EGT - cylinders 3 (which has a 140 psi compression) and cylinder 2 (can't really reach 1) have an EGT of only 200 degrees. A 200 degree EGT difference just screams somethings wrong - but I can't find the problem.
There's one of those early EGR systems under the Holley but there's no real way to test it - and I don't think it would only affect cylinders 1, 2 and 3 (which are all adjacent on the right side). Is it possible that the Holley is built such that half of it supports cylinders 1, 2, 3 and 4 while the other side supports cylinders 5, 6, 7 and 8? By the way - don't know at this point exactly which Holley model is installed.
So - to summarize - have a very rich poor running 460 with no obvious problems, and 3 of the 4 cylinders on the right are running EGTs 200 degrees less than the 4 cylinders on the left side.
I'm stumped and open to any suggestions. Thanks in advance.