Greetings all, I'm brand new to the forum and to this neat little truck, a 1991 Ram 50. I bought it from my brother-in-law over the weekend, and drove it from Virginia to Georgia yesterday. It seemed to run pretty good, with the exception of what sounds like a detonation rattle whenever I was asking it to pull, like going up a long hill, or accelerating to pass.
The truck has 89K on it, and I know it just had a timing belt change a few thousand miles ago.
So, pinging issue aside, it also has a "check engine light" on, but I can't find anyone who has the right cable to read it. I thought the emissions inspection station would, but they didn't either. The ran the emissions test using the tailpipe sniffer test. It passed on some and failed big on some.
- HC ppm - Read 28, Allowable 194
- CO% - Read 0.0%, Allowable 2.19%
- NOx ppm - Read 4279, Allowable 1258
- CO + CO2% - Read 14.54, Allowable 6.00%
So, where do I begin? What are the likely culprits for the high NOx readings? I have a factory service manual on order (from an eBay auction), but it's not here yet.
Any way this is related to the timing belt change? If the belt were one tooth off maybe?
I'm hoping that whatever the fix is, it fixes the detonation noise and the emissions, I have a suspicion they are connected.
Thanks in advance for your help!!