3800 SWAP PROBLEM (Page 1/2)
Lou6t4gto APR 23, 12:31 AM
a 3800SC Partial swap into an 86 coupe. I finally got the fuel and battery hooked up and the Engine Will Start right up and "idle", stock oil gauge pegs,(Mech gauge idles at 65 PSI)( will get a new ac oil sender for 88). Temp gauge reads 200 "as soon as the key is turned on", (already tried 2 new "senders", same thing).
key OFF the TACH reads 0, turn the key to the on position and it reads 2000 RPM, Start the engine and it only reads 1000 RPM No Matter what the RPM Actually is !,
AND, it IDLES well, but anything else, it runs like it has crossed plug wires ! Has brand new TPS. spark plugs and wires. no idea how Long the engine SAT idle before installation, or how many miles on it . Ideas ???? injectors ? will check "pressure" tomorrow

[This message has been edited by Lou6t4gto (edited 10-12-2020).]

OntarioKev APR 23, 01:29 AM
What do you see on your OBD2 scanner? idle RPM, what happens as you increase RPM, how does the MAF readings look? Are you seeing many misfires?
Lou6t4gto APR 23, 01:20 PM
all I have is one of those hand held "Code readers" , only thing it said was TPS was bad, so I replaced it. ** why is the TACH acting "Wacky"???** runs, literally like 2 plug wires are crossed. but they are not. a Coil? ( I'd check it with my timing light, but they "moved" the battery to the front so the light cannot reach it). INJECTORS ? (going to check with a pressure gauge).
olejoedad APR 23, 02:04 PM
You can't adjust the timing anyway, nor is there a flag or markings on the balancer.

Look for discolored or rusty terminals on each coil, it's a good indicator of spark health.
The coils ground through the collar around the mounting screws, make certain the collar and fasteners are bright and shiny.
Make sure the ICM is well grounded to the engine block.
Use a spark checker to check for a bright blue/white spark.
Check spark plug gap.
OntarioKev APR 23, 03:59 PM
You should look into getting a proper OBD2 scanner that can show you live data, it can really help out with issue. Torque (I think is the app name) is a nice cheap one that only needs a Bluetooth OBD2 connector to use.

You can see what the PCM is actually seeing/reporting. Then you know if its the Fiero dash/wiring or if its a real issue with the engine.

Now you know that you have an issue with the engine but with being able to view live sensor data you can look at MAF readings, misfires per cylinder O2 sensor voltages, fuel trims, ecetera.

This can help you track down whats happening. For example you can look at O2 voltages and determine if there is something off with either the sensor or fueling. You can use cylinder misfires to track down a bad coil/wire.

I am not sure how you have been tracking down issues on obd2 cars without access to this information. Quite often sensors are messed up but not bad enough to throw a code and you can spot it this way.

I personally use HPTuners as I do tuning as well, but the scanner function is invaluable for tracking down engine issues.
Lou6t4gto APR 23, 04:55 PM
I wasn't going to use the timing light to "TIME IT", I was going to use it to see if there was indeed SPARK going to the plug.
what I DID FIND: No Ground "PULSE" going to #4 Injector ! all others are fine.
so, am I right in assuming it's either the HARNESS or ECM ????
Lou6t4gto APR 23, 06:30 PM
so no pulse to #4 cyl injector, #46 blue coming From ECM, will check tomorrow. but whats with the TACH ?
OntarioKev APR 24, 01:35 AM
Tach could be CPS, wiring issue to the pcm, wiring issue from the PCM to the dash, or the dash gauge itself....

If by any chance your handheld scanner can show you RPM live data, you can find out if the issue is before the PCM, or after cutting your items to check in half.
jb1 APR 24, 03:06 AM
Lou check in 46 of blue c1, it may have possibly got over looked and got mispinned, if pinned correctly use a continuity meter and make check to see if wire got broke.. as far as gauges is there good ground path between block and body ? Tach wire runs from pin E of ICM connector on main harness to c3 of the c500. It does not go through pcm.. I missed your call tonight as I work 2nds and just got off .. will return call when I get up later today.

[This message has been edited by jb1 (edited 04-24-2019).]

Lou6t4gto APR 24, 11:43 PM
WAS a" Bad WIRE" on #46, replaced and it runs fine. still have to find a TACH and a TEMP gauge I guess