89 Silverado Knock When in Gear Under Load
- #two
If it's a roller cam 5.7 from a Caprice then the engine is likely a Vortec type.... was this originally a Vortec? Did you retrofit a throttle body/intake onto information technology? I'thou not sure that the Caprice ever got a throttle body blazon that also had roller cams only apparently I could be wrong there.
Either way, you sound to me like you either have bad fuel pressure coming in, or you have bad spark timing. I tin't remember what fuel force per unit area a TBI should be running at. I've had several fuel filters go clogged on me from a bad tank of gas, and it caused EXACTLY the aforementioned symptoms--- ran like a turd at whatsoever load.
I've likewise had (and.... currently have 
) distributor caps get fried and cause this. Even 4 calendar month old caps.
190 is smashing compression, I've seen 185 on several L31 vortecs with 200K+ miles.
But know, if this were a Vortec anything like the L31 vortecs that come in 1996+ trucks, at that place'due south a practiced take a chance you really are fighting timing. The L31 Vortec'south timing was basically not adjustable. The just thing you had control over actually was a very tiny twist of the distributor to suit cam retard, literally only a couple degrees of turn.
- #4
Until you verify the pressure don't presume that information technology is not a fueling issue. These engines volition commencement and run with depression fuel pressure level simply tin exhibit drivability bug. Fuel pressure is 9-13 psi. Bank check your EGR, Disconnect the vacuum line and plug it. Take it for a test ride to see if it goes away. I just had this same problem with my 92 K 1500. Information technology had a stumble under load and I had a heck of a fourth dimension finding the crusade.
The EGR acted normal at idle, I could lift the pintel off the seat and it would induce a leak and cause the engine to miss/run rough like you would wait. I ran all of the diagnostics and every thing checked out. It drove me nuts for a while, so, I fired up the parts cannon and got lucky with the commencement volley, manifestly the EGR was gummy and would not operate smoothly. With a new EGR the problem disappeared and it runs fine. Peradventure this volition help. practiced luck.
- #half dozen
1. Roller cam LO5 in autos was common in the early '90s. I put one in my K1500 almost 20 years ago. The Caprice LO5 has flat-superlative pistons instead of the K1500 LO5 dish pistons. Ran flawlessly on the stock calculator and PROM.
two. You don't have an EGR, and it'due south non setting a lawmaking? That's a problem right at that place.
iii. 190 psi pinch seems actually high. Certain the gauge is accurate? Having the cam timing overly-advanced could practice that, too. I examination my pinch tester gauges now and so by connecting them to shop air force per unit area. One pinch gauge tin can exist compared to the guess on the force per unit area regulator. 2 pinch gauges can be compared to each other AND the gauge on the pressure regulator.
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iv. I'd even so desire to know the actual fuel force per unit area Under LOAD. A weak pump could supply appropriate fuel force per unit area at idle, merely not supply enough during heavy throttle, high RPM.
5. Connect a scan tool, await at the data stream. The answer is near certainly in the data stream.
Final edited:
- #10
The temp sender in the cylinder head has nothing to due with how the truck runs. It is for the gauge only. The Engine Temp Sensor in the intake is the one that the ECM uses to brand adjustments. Make sure that the ECM tin can recognize a mistake code, tap the block near the knock sensor and meet if the ECM sets a code or unplug the ECT in the manifold and see if the ECM sets a code. try a tap test on the ECM and see if information technology changes anything. These trucks tin can start and run with a faulty ECM.
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89 Silverado Knock When in Gear Under Load UPDATED
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