Hello all

This past weekend I installed my new exhaust on the Z. I used the stock header and MSA premium exhaust. The install went well, took forever but well. When I got the Z back and running it feels like it looses a lot of power between 2500-3500 rpm. It has for-firing occasionally (ignition in the intake). From all this I want to say that the car is running lean? Has anyone had this issue when installing new exhaust?

Would the fix be as easy as riching the mixture up a tad or is there more behind this that I don't know about?

Thanks all

Jan

Edited July 12, 201113 yr by Pomorza

Was it running better before the new exhaust? could you have a mainifold leak?

Update

Turned out the #3 injector and a few of the plug wires were not correctly connected to where they should be, the previous problem has been fixed. New problem, was driving a friend home and as I turned and went to accelerate the car did nothing. Pedal was nearly 75% depressed and it didn't respond to the acceleration. Did it once more and then seemed to clear up. Ideas?

Jan

Update

Turned out the #3 injector and a few of the plug wires were not correctly connected to where they should be, the previous problem has been fixed. New problem, was driving a friend home and as I turned and went to accelerate the car did nothing. Pedal was nearly 75% depressed and it didn't respond to the acceleration. Did it once more and then seemed to clear up. Ideas?

Jan

Check all of the wires on the thermostat housing, mine had bad connections and it would cut out completely around 2300 rpm and would not rev any higher

Check your TPS, the FSM shows how to test it (very simple).

None of this should have anything to do with the exhaust. I'd look for bad/crusty/dirty connections and crumbly connectors. You can buy all of the 2-conductor Bosch style connectors from a seller named f0rrest on Ebay.

http://cgi.ebay.com/ebaymotors/injector-connector-kit-6pc-datsun-280z-280zx-300zx-_W0QQcmdZViewItemQQhashZitem43a04f8954QQitemZ290452375892QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

Same connectors for the CTS, cold start valve, air regulator, and thermotime switch. Have the f0rrest put together a 10-connector set for you, or order another set for a 4 cyl Jeep. I'd also suggest getting an extra connector to use for testing/debugging.

Found something interesting.

Was going through all the wires to make sure that they were all connected. All is good except for the BCDD, which for some reason was unplugged. After some time I found that, not only is it not plugged in but the wire that goes to it is ripped out of the said housing. Could this cause any symptoms?

"Same connectors for the CTS, cold start valve, air regulator, and thermotime switch. Have the f0rrest put together a 10-connector set for you, or order another set for a 4 cyl Jeep. I'd also suggest getting an extra connector to use for testing/debugging. "

When you say ten connector set for you what exactly are we talking about here?

Jan

Edited July 13, 201113 yr by Pomorza

Just contact the seller, and ask him if he'll sell you a set of 10 connectors -- or maybe 11 for the spare. He can put together a custom auction for you. With 11 connectors, you can replace all of the 2-conductor Bosch-type EFI connections and have a spare for testing work.

I forget how the BCDD works, and I don't know whether having it disconnected might result in problems. However, the BCDD on most of our engines has long since stopped working, with replacements NLA. Many/most have already been removed.

Update #2

Took nearly all the major connectors off and cleaned once again with cleaner. The TPS was rather dirty and I'm pretty sure needed the cleaning. Drives like new for now. As for connector updates. I plan on upgrading my fuel injection in August so that will be included.

Thanks for the help

Jan

Update #3

So my problem has become worse. Over that past two or three days it would run fine one day and horrible the next. Today I was driving a friend down to see some things in south tucson and the car began to buck, power loss would come and go at 2500-4k rpm. No matter where the pedal was it would not accelerate. I looked under the hood and found that the coil wire would zap (shock) me when I touched it with the car running. Replaced the wires and it did this bucking once more and hasn't all day. Does anyone have any ideas?

Jan

What do plugs look like? Black and fouled?

What about an intermittent vacuum leak...like when you went around that corner, something shifted out of place, air leak, cough sputter, then it sealed back up???