Spyder injector assembly

[gmcman101]

My 97 was running rough so I took to a guy that has a diagnostic tool.(computer) He said the cylinders 4 and 8 were throwing a misfire code. Said the injectors were probably bad. I bought a used spyder assembly and changed it today. Put a new gasket on the upper manifold and started it up. The thing runs worse then ever. Barely idles and will not gain RPMs with the throttle depressed. Does something need to be reset? Can the spyder assembly be tested out of the vehicle. I'm pretty certain I put every thing back together correctly.

[ct9a]

Sounds like it might be a fuel pressure problem. Perhaps a stuck open injector?

[Badbrad469]

spider injector has only one "injector" and supplies the fuel to each cylinder through poppet valves. if the spider assembly isn't seeing the correct pressure then it won't send fuel. usually when u replace the spider unit, u need to replace the "nut kit" too.. the nut kit is the fuel lines that go through the manifold into the injector. take off the upper intake and turn the key over and see if gas is coming out from the lines or where the o-rings are.

[gmcman101]

The gasket kit came with a throttle body gasket and two o-rings, I did install them. I might have put a little to much pressure on the pressure sensor, if that was cracked could it be the problem?

[gmcman101]

Sorry, I said pressure sensor but after surfing a little, it's the MAP sensor. Would that cause it to run terrible.

[ct9a]

If the MAP sensor is damaged, then yes, it can cause problems if it's malfunctioning. The MAP sensor is how the ECU measures how much air is present/being drawn into the motor and decides how much fuel to add.

[gmcman101]

I'm not to sure if the seal is tight around the plug in for the spyder assembly either. Maybe getting air through there? It's supposed to be a balmy 40 something this weekend so I'll check it out then. The trucks been down for some time now, so I was a in a hurry to put it back together. I should of known better. Thanks guys, any input is appreciated.

[ct9a]

Spray some carb cleaner around where you think you might have a leak, you should hear the motor rev up (or stumble, can't remember, it's been a few years) when you spray a vacuum leak.

[gmcman101]

I'll give it a try. Thanks, again.

[gmcman101]

Well, I took everything apart again and carefully reassembled. Still no difference. It will only idle and with a terrible lope. I don't think the nut kit would need to be changed because it don't have one. The gas lines do not go through the manifold they run right on top and enter next to the spyder plug in. Does anyone know if the poppet nozzles can be changed on the spyder assembly. I can't figure this out and it very frustrating. Help!