WANTED 1990 Q45 CAM POSITION SENSOR

[slshearer]

My 1990 Q45 has an intermitant problem sometimes when starting the engine will miss (run rough) or surge, I took it to Gwinnett Infiniti and had the code downloaded, code 11, could be the connector to the sensor. If you have any info on diagnosing/servicing this part please email me. I would like to buy a spare so if you have one let me know what you want shipped to 30019 (Atlanta, GA)

Thanks [email protected]
Modified by slshearer at 8:02 PM 7/20/2008

[Q45tech]

The CAS has 2 connectors one on body and another on a pigtail.

Typically they fail because of internal rust and dirt build up causing drop outs in the 360 degree pulse output.

We usually recommend a new oem one as dismantling and cleaning is an almost impossible task. I have destructively analysed a half dozen .

90-93 is a direct replacement as 94-96 use a single multiple circuit connector.

Check with T3 in Dekalb to see if they have a decent used one.

[slshearer]

I will give T3 a call, is there any danger of harming my engine if I have to drive it a few miles till i get it fixed? T3 is almost 75 mles from me so would you have it towed or ???

Thanks!Stewart

[slshearer]

I called T3 in Roswell and spoke with someone who answered the phone, I told him I had a 1990 and he advised I needed to replace all my injectors, cost $2200, he also stated that it was a fuel related problem with reformulated gasoline, when I asked him if I would experience the same problem with the new injectors he said it was possible they could fail due to the as being sold today! Wow $2200 and I am still faced with the possibility of not having the repair last, I guess 1st Gen owner will be parting out their rides based on this problem. SAD day for us Q owners!

[ScottJackson]

Yep, you need to ALWAYS use gasoline with no ethanol. Not 10%, none. You can get a set of Venom cheap injectors off Ebay for a 300zx for about $550-600 that will work. Some people like those injectors, some don't. If injectors are starting to die, it's best to just do them all with new ones as more are soon to follow.

[slshearer]

Well I don't know what everyone is gonna do with their cars if injectors cannot work with re-formulated gas? Guess that is one way the Government can get rid of older cars by making it so expensive people will junk them cause they can't afford to fix them.

[npez]

I called T3 in Roswell and spoke with someone who answered the phone, I told him I had a 1990 and he advised I needed to replace all my injectors, cost $2200, he also stated that it was a fuel related problem with reformulated gasoline, when I asked him if I would experience the same problem with the new injectors he said it was possible they could fail due to the as being sold today! Wow $2200 and I am still faced with the possibility of not having the repair last, I guess 1st Gen owner will be parting out their rides based on this problem. SAD day for us Q owners!

slshearer,

There's a post somewhere on here regarding changing the fuel rail, etc. so your pre-94 motor can use the phase 2 injectors. These injectors are pintle-less and they are not prone to the ethanol issues of the earlier injectors. As mentioned the injectors are the same as those in the 300ZX - I got mine (I have a 94 motor) from Z1 motorsports and I think the total tab for 555cc (which actually flows 615cc) injectors came out to about $1100-$1200 with all the o-rings and everything that was needed. You should be able to get the 370cc injectors for a reasonable price. I can give you mine if you want them after I put the 555cc injectors in - but that's still a month away.

Thanks,Nick.

[slshearer]

Thanks for the info, I would definately be interested in getting your them when they are available, let me know when your ready and we can work out something for sure!

Thanks again!

Stewart

[Q45tech]

It appears that the E10 causes the injector plastic body to swell and pull apart the internal connection between the coil and the external connector.

We have seen about 25+ cars fail with 1-3 injectors after E10 was introduced to ATL Metro on 3/01/08. It took 6 weeks for my Q. Some took 4 weeks some 9 weeks. 5 local Infiniti dealers are reporting roughly same situation.

At first the problem was with 90-93 however a month later 94-95 started to fail and now the problem is evenly distributed based on high miles.

We usually recommend that 4 be replaced [an entire bank] to minimize repeat labor............4 x $200 + $680 for plenum removal.

So far so good it has been 2 months since I replaced 4 [1.3.5.7] on mine. The even bank hasn't been touched as a control.

Important to change fuel filter frequently as any water in E10 will cause corrosion of fuel pump commutator.

As a side note we are seeing our first Lexus LS400 fuel pump failures at the exact time of injector problems............?

Prior to E10 we probably changed 8 injectors on Q in 13 years of business, we changed 9 the first week the problem showed up but then again all had 100,000+ miles.............mine had 318,000 miles so who can complain?

Nissan wrote a letter to California CARB in 1994 warning them that changes to gasoline would cause problems at 100k even before E10.

[npez]

Dennis,

I had a couple of questions & comments - I guess it's my analytical nature

It appears that the E10 causes the injector plastic body to swell and pull apart the internal connection between the coil and the external connector.

Is this something that has been visually confirmed after injector inspection? I wasn't sure if "appears" as stated is a hypothesis or a verified fact.

We have seen about 25+ cars fail with 1-3 injectors after E10 was introduced to ATL Metro on 3/01/08. It took 6 weeks for my Q. Some took 4 weeks some 9 weeks. 5 local Infiniti dealers are reporting roughly same situation.

At first the problem was with 90-93 however a month later 94-95 started to fail and now the problem is evenly distributed based on high miles.

There is definitely a possible correlation as you stated. What I would question is why 1-3 injectors? They are all the same, are all exposed to the same E10 for the same duration. Do the same people with the 1-3 injector failure come back in within the next 4-9 weeks with additional failed injectors? This would establish deviation. Being these parts cross-reference to other nissan vehicles, you would expect that these issues would "migrate" to other Nissan models (300zxs, etc.) have you heard anything similar from Nissan dealers as well?

At any rate though, within a year a significant amount of older infinitis/nissans will be affected. I would call that an epidemic.

So far so good it has been 2 months since I replaced 4 [1.3.5.7] on mine. The even bank hasn't been touched as a control.

If the failure can be visually confirmed I believe this will be a valid test. If not your "control" group is not representative of the "population". It's like a drug company testing the effects of a drug and using 15 year olds in one group and 80 year olds in the control group. If your other 4 injectors are old, age or other factors could attribute its failure versus the ethanol in E10.

Important to change fuel filter frequently as any water in E10 will cause corrosion of fuel pump commutator.

As a side note we are seeing our first Lexus LS400 fuel pump failures at the exact time of injector problems............?

Prior to E10 we probably changed 8 injectors on Q in 13 years of business, we changed 9 the first week the problem showed up but then again all had 100,000+ miles.............mine had 318,000 miles so who can complain?

Nissan wrote a letter to California CARB in 1994 warning them that changes to gasoline would cause problems at 100k even before E10.

I fully agree with you on the other points. Also, the problems are further complicated if the car sits around (not a daily driver) as the ethanol separates from the gasoline which causes more problems in addition to the water. I've read that fuel stabilizers can help with this - but haven't tried it myself.

BTW - the auto manufacturer lobby also wrote congress regarding E10 and congress' response was something to the tune of older more polluting cars will be retired more quickly this way. That's politicians for you!

Great post!

Thanks,Nick.

[slshearer]

Apparently the early Q45 and 300Zx use the same injectors and when parked the electrical system provides 12 volts to the injectors., It has been suggested that the recent injector failure is causing a chemical reaction of the FI contacts causing the injector connection to fail.

If this theory is correct, then by removing the supplied 12 volts to the injector circuit should resolve this problem. This could be done by removing the battery connection which would prove to be very inconvenient or bypassing the existing circuit which would disable the voltage to the injectors.

My question is what relay supply's the 12 volts to the injectors?

Could the electrical system be modified to provide a switching relay which would cut the voltage off to the FI circuit wen the car is not being driven? If not possible could a switch be installed which would disable the 12 volt circuitto the injectors when parked.

Is the corrosion of contacts in the injector caused by the injector handling the modified fuel only when the vehicle is being not driven or is it the fuel chemical re-action to the plastic housing? If it is the reformulated gas disolving the plastic this would not fix the problem.

I ride motorcycles a lot and like very bright running lights which the standard headlight circuit cannot handle, to resolve this a new 12 volt main line is routed to the new HD switching relay and a low 12V connection is pulled from the accessory side of the key, this completed the circuit and then the relay provides the main 12 volt line to the lights when the key is turned on, the relay is also grounded to the chassis.

I think we all need to get serious about this problem, If it costs $1500 to $2500 to replace your injectors with no way to stop the problem then there is going to be lot of great cars going to the crusher!

ThanksStewart

I have started a new Forum on this subject. FUEL INJECTOR FAILURE SOLUTION FOR 1st GENERATION Q45, & 300zx

Modified by slshearer at 7:15 AM 7/26/2008
Modified by slshearer at 7:16 AM 7/26/2008