[tirwin]

Blue,

What is the temperature in your garage? It’s worth noting the climate differences between Houston and Calgary. CIS is sensitive to temperature.

Let’s talk about what a cold start means. A “normally” operating engine prefers an Air Fuel Ratio (AFR) of 14.7:1. 14.7 parts air mass to one part of fuel mass. When the ratio is less than 14.7:1, say 12:1, it is said to be rich. When it is more than 14.7:1 it is said to be lean. Rich is needed for cold starts and when you have your foot on the go-fast pedal.

An engine needs a richer mixture on cold start for a few reasons.

1) colder air is more dense, so the same volume of air at a lower temp will have more oxygen atoms than the same volume at higher temps. this must be accounted for in the cold start process.

2) fuel is harder to vaporize when it is cold

3) on a cold engine, the injected fuel can condense on the surface of cold parts meaning that less than the ideal amount of fuel is available to burn, so the EFFECTIVE AFR is lower than intended

So on a cold start — when it is actually cold outside — engine management systems need to compensate for this temperature differential and supply more fuel (a richer mixture). Whether it’s carbs or CIS or EFI, the principle is exactly the same. They just go about it in different ways.

CIS is a mechanical system that is heavily dependent on proper fuel pressures to function correctly.

To properly diagnose your CIS system you absolutely must have a fuel gauge like Tony suggested.

The basic tests are:

1) system pressure — making sure there is enough pressure from the fuel pump and fuel distributor

2) cold control pressure — making sure the AFR is correct on a cold start (HIGHLY dependent on outside ambient temperature)

3) warm control pressure — normal operating

4) residual pressure — affects warm starts

Get a set of gauges and do the tests methodically. Guessing is an expensive and a frustrating process.

The primary part of focus is the WUR (warm up regulator).

Another piece of advice is to make sure you have all the correct parts for your model year. It is not uncommon to see cars that have the wrong parts after 30+ years. Whether it was a well-intentioned person who simply didn’t know the differences or a lazy mechanic... the point is, you can chase your tail with the wrong parts.

Suggest you look at my CIS Troubleshooting for Dummies thread. Test procedures and links to parts references are all in there.

Do some reading, get the gauges and then build a test plan. Plenty of people here to help. Ask for help if something doesn’t make sense.