Can a bad coolant temp sensor cause backfiring and jerkey acceleration?
 

My 84 GSL recently got a new cooling system...hoses, koyo, thermostat, and water pump. No more over heating, but they busted they busted the wires on my coolant temp sensor, the one in the block near the alternator. They ordered the wrong part three times so yesterday I biked to the shop, picked up the sensor, took it to a friend soldered the wires back on, took it to the shop, installed it and now the manual choke was working and staying out upon cold start. The problem is that it now drives like crap and backfires like crazy, especially during deceleration. I replaced the cap and rotor today, checked for an exhaust leak and vacuum leak, but nothing has helped. Any help would be much appreciated.

if the engine has over heated the engine compression should've been checked first before all that work was put into it. That sensor is a possibility, but you need to do more testing before throwing more money at it....unless you like throwing money around, if you do, throw some my way

Sounds crazy, but I would check your battery connections. Since you just had it in for work they would have at least disconnected your ground and it may not be securely connected.

Tried to get the compression tested today as well as a check and adjustment of timing, but they didn't know a thing about rotary engines and suggested Jay at a local Yakima shop; talked to Jay yesterday and he can't take a look for a week...I guess he's the only guy in Yakima, Washington with any rotary knowledge. Eliminated the coolant temp sensor, also known as the coolant fan temp switch as the reason for my out of the blue rapid fire backfire that started when I picked my car up from the radiator shop. I disconnected it, the choke no longer worked, wouldn't stay out, but the backfiring issue did not change at all. I doubt I've blown my apex seals as I did not let the engine get very hot before addressing the cooling problem and just yesterday got it up to 105 mph. When I talked to the radiator shop guys yesterday, I asked them if they had replaced any small vacuum lines or possibly forgotten to reconnect one of them. They told me they had seen a broken line with oil leaking slowly, and had spliced it together with some tight fitting tubing. Here is a picture of what I'm talking about. I have no idea what these small white plastic tubes are for???? One is sliced together and the other has a very small leak and I can see an occasional bubbling when the engine is running. They run from the carb down to I think the oil pump? Just went out to take the pics and can see that the leaking has intensified. Somebody please tell me that this is why my kick ass car is running like crap, even though it still goes 105mph, the name of these tubes and the best place to buy replacements. Much thanks Erik

Bit of advice, if the shop doesn't know how to do a simple compression test on a rotary, don't take it to them for normal maintenance either. Who knows what else they messed up and may not have told you.

Sounds like they broke a line that goes from the oil metering pump to the carb. Their fix will not work and will fail. This line is critical for maintaining the life a the roraty. It supplies oil to lubricate the seals/rotors. These OMP lines are no longer available new.

https://cimg5.ibsrv.net/gimg/www.rx7...a94d488ae2.jpgBroken line spliced but leaking, the other one looks empty, but I can see air bubbles from a small crack when engine is running.
https://cimg6.ibsrv.net/gimg/www.rx7...1937691ac0.jpgWhat are these tubes called? Where can I get them? Rock Auto?
https://cimg7.ibsrv.net/gimg/www.rx7...5967122ae8.jpgCould these damaged lines cause diminished performance and small rapid fire backfire?

I found the oil metering lines new at Atkins Rotary for $50. Are those busted and leaking lines most likely the reason for the backfiring ??? Thanks for the help..