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76Datsun280z

Sticky EFI thread, please chip in FI guys!

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I'll have to check the numbers on his and I won't be able to do that until tomorrow. I do believe that the 75-76 are interchangable. Remember, I have no way of testing them (but I'm working on something that might allow me to do that), but I assume it's good because the car was running when he got it but he took the engine out the put it in is 240Z. I'll get back to you on this as soon as I know something because I'm sure it will cost a lot less than $200.

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Hi Zcar, I got my car running finally. ended up being a dirty connection on the temp sensor. I would like to point out that there are 4 temp probes under that top radiator hose located on the thermostat housing, I found 3 of them. thanks to this post I found the fourth one and it was the temp sensor. I was trying to match a temp sensor to my thermotime switch. till I looked at the link to the fuel injection bible. on page 28 is a picture of the thermostat housing with the 4 probes. now for that Road Test! Great site. thanks All

Edited by Fordlover

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I got around the block with the car running fine,had to jump the starter relay as the key won't start it, almost had me thinking about keeping this japanese bucket of rust, then it started the lopeing trying to die crap. it did actually die when I got in the drive way.I need this car to run been 2 years now if it wern't for the rebuilt motor and the new tires on it I would have scraped this rice burner! Yea hows that for a RANT!

OK I will spend the 20$ for a temp sensor tomorrow. But I need to also know where the vaccum resivour gets its vaccum from. there is a hose or 2 missing.I downloaded and searched the fcm and didn't see a vaccum diagram. I did search the site and saw a vac diagram posted on a thread about A/C heater problems but it was for a 78 model.

heres what I am dealing with a 4/75 per data plate on the drivers door jam. So what year is it? it is fuel infected also. not a big fan of fuel injection. automatic transmission which seems to work fine. I have today took the longest ride it 4/10 of a mile. WOW!LOL not quit a trip to FLA.I live an hour south of Atlanta. I need to figure where the vaccum relays get there vaccum from as that is one of the hoses missing. any help might just save old RUSTY>

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I need to also know where the vaccum resivour gets its vaccum from. there is a hose or 2 missing.I downloaded and searched the fcm and didn't see a vaccum diagram. I did search the site and saw a vac diagram posted on a thread about A/C heater problems but it was for a 78 model.

heres what I am dealing with a 4/75 per data plate on the drivers door jam.

It's been 10 years since I owned my '77, but IIRC there was a single vacuum line which ran from the vac diaphram under the dash to the manifold and the other nipple on the manifold was for a "idle helper" of sorts which bolted directly to the manifold. Regardless, if they're both plugged either should affect the drivability of the car.

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Good sticky BTW, I'd like to add my $.02. I see a lot of talk about the cold start system. When I owned my '77 back in the 90's I swapped out the fuel rail with one from a ZXturbo which had larger diameter tubing, but the catch was it did NOT have a provision for the cold start valve so it snowballed from there.

I discarded the air regulator, cold start valve, thermotime switch, and the coolant lines which ran to a base plate sandwiched under the air regulator. I pipe plugged cold start hole and the others. It certainly cleaned up the engine bay considerably and the car ran GREAT without all that garbage. This until the first snowfall in Wisconsin.

Also, I see no mention of the BCDD valve (hangs under throttle body). It's there to "hang" the rpm's during shifts and reduce hydrocarbons. The problem is quite often it "hangs" too much and becomes quite annoying. Fortunately the aftermarket throttle bodies, and perhaps the other OEM ones people retrofit. do not have a provision for this and it can be eliminated.

Edited by preith

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I'd like to add something here. I see where a lot of people are asking about fuel injectors. Which ones to use, new or remanufactured, and so forth. The following information maybe known, but here it is anyway. The link comes the Reuters website. It is a stock listing for Standard Motor Products. Under "Full Description", paragraph identified as "Engine Management Segment". As you can see Standard Motor Products makes several different brands. Are they all made to the same specs? That's a good question.

Standard Motor Products Inc (SMP) Company Profile | Reuters.com

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Ok, so I am a novice but learning quickly thanks to all of your posts. Would have never attempted to upgraded alternator or drop my gas tank and recoat without this forum among other things. So bare with me. But it would be nice to have a spreadsheet or something similar (not sure if everyone has excel) that list each part, a description/function for each part, location and photo of each part (earlier post would probably work fine,), a column of symptoms that part is bad or needs adjustment based on everyone's experience, add a column with tests etc that can be performed to check each part, and finally the location in the FSM that spells out some of this information. Maybe this is to much work for someone or several people to do but for someone like me diagnosis is the hardest part.

One last note, you guys read the FSM and it makes since. Sometimes when I read the thing it looks like Chinese. I know that some of this only comes with experience but every little bit of clarification helps.

Again, thanks to all. You guys are amazing. I hope to be able to help others soon.

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One last note, you guys read the FSM and it makes since. Sometimes when I read the thing it looks like Chinese. I know that some of this only comes with experience but every little bit of clarification helps.

That is probably because most of it has been translated from a japanese manual and most probably by someone with english not being their native language.

Some sections have sentences that throw you of a bit. Takes a bit of getting use to, but you will get the hang of it.

Chas

Edited by EuroDat

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Yeah, it's kinda like the Chinese picture-instructions for assembling furniture. You can be sure if you're supposed to insert a screw into Hole A, or screw-up Hole A...

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I have been working on my parents 1978 280Z and was wondering if any of you fine gents could point me in the direction of appropriate FSM for this year. On several of the forums so far I have seen a lot of confused folks making post about the location of the fuel injection relays on this year of car. It is different from earlier years along with the ECM pin mapping being different from what is show in the "EFI bible" for the 75 models. I am sure there are other differences for this year, and I would like to have the actual documentation to know what's up and what's not.

The car is in unbelievable shape for its age, but has been sitting for years. I just got it started yesterday, but it only runs for a few minutes before dying. I got this far using the older manuals and my 15 years of working on FI cars, but sure could use some help getting this old girl back on the road with the right documentation.

 

Thanks in advance!

 

PS Amazing site! This is my first time in the "Z" community and so far I've very impressed with the people here.

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You can download it from this site. http://www.xenons30.com/reference.html

If you scroll further down to the "other" section you will also find the EFI bible. I have read that the EFI bible on the xenon130.com site is better, but I can't confirm it.

Goodluck

Chas

EuroDat,

Thanks for the help and directions to the above page.Got the 78 FSM now.  I just checked out the EFI manual that is posted and it is the same 1975 model year that I currently have. Which unfortunately does not match up with the ECM 35 pin connector on the 78's. There is a nice trouble shooting section in there, but my 78 does not have some of the pins listed. I believe they have changed some of the electronics and its making it hard to figure out just what could be causing the running problems. 

Thank you again for the link!

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In the EFI manual on page 53 "air flow meter fuel pump contacts" test for car not starting is says to check continuity between leads 10 and 20 with the AFM flap in different positions. However, my North American (non-California) model does not have a pin 20 in the ECM connector. Anybody got any thoughts on testing this?

 

Cheers!

 

 

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The newer Fuel Injection Guidebook is in the link below, it's for the S130, not S30.  It's from 1980 but covers all previous years.  1978 doesn't use the fuel pump contacts, it uses the oil pressure switch or the alternator current, through a relay.  You'll need the 1978 FSM, Engine Fuel chapter, to see that.

 

Does it run for an actual few minutes or a measured 15 - 20 seconds?  The word is that for 1978 if you disconnect the oil pressure sender that the fuel pump will get power when the key is On.  It's a flaw in the design, but could be handy.

 

http://www.xenons130.com/reference.html

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I have heard from others about these issues with the 78 model. On the 78 they started changing things a bit and some things seem more like the S130. Thats why I mentioned the other EFI bible on xenons130. I have a 77, thats why I can't confirm it.

Maybe Fastwoman will see this and chip in. Sarah has a 78 and knows a lot about that model year.

Im on a smartphone so I hope this is not to challenging to read.

Chas

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The newer Fuel Injection Guidebook is in the link below, it's for the S130, not S30.  It's from 1980 but covers all previous years.  1978 doesn't use the fuel pump contacts, it uses the oil pressure switch or the alternator current, through a relay.  You'll need the 1978 FSM, Engine Fuel chapter, to see that.

 

Does it run for an actual few minutes or a measured 15 - 20 seconds?  The word is that for 1978 if you disconnect the oil pressure sender that the fuel pump will get power when the key is On.  It's a flaw in the design, but could be handy.

 

http://www.xenons130.com/reference.html

It runs from a cold engine for about 2 min and then stalls out. If I let it cool down then it will start up and do the same thing again. It runs rough during its running time, but it can be reeved up to about 3-4K. Once it starts to warm up, and after it dies, it wont start again for a while.

Thanks for the tip on the oil pressure sender and fuel pump interlock bypass. 

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Zed Head and EuroDat thanks for the help. I just got the EFI manual for the 78 and I will have to get back under the hood and steering wheel and see where the pins go and what is working and what is not. 

 

Cheers

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Does the exhaust get a gassy smell before it dies?  Kind of sounds like your coolant temperature sensor is disconnected, causing the ECU to supply fuel for a cold engine.  Or that you have a vacuum leak and the mixture is only rich enough to overcome the leak(s) when the ECU is supplying extra fuel when the engine really is cold.

 

The Guidebook shows how to check resistance of the coolant temp. circuit at the ECU connector.  That will show you if the ECU is getting good information.

 

Once you run out of the simple checks, the best route is to get a multimeter and run through all of the electrical tests.  They don't take as long as you would think and when you're done you'll probably have found a few simple things to make better in addition to maybe finding the big problem.

 

If everything checks out then you can move on to the odd problems, like fuel pumps that are corroded and overheat after a few minutes of running.  Two of us have had those.

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Another website to get usefull info is AtlanticZ http://ww.atlanticz.ca. Check their Tech Tips. If you are new or firmiliar with Zeds its has a lot of handy tips. You will see Blues Zed in a lot of the how to's.

Your problem sounds much like what Zed Head already mentioned, so I wont repeat it. The temp. sensor cable often gets roadster over time and the connector falls apart. That happened to mine.

Chas

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Does the exhaust get a gassy smell before it dies?  Kind of sounds like your coolant temperature sensor is disconnected, causing the ECU to supply fuel for a cold engine.  Or that you have a vacuum leak and the mixture is only rich enough to overcome the leak(s) when the ECU is supplying extra fuel when the engine really is cold.

 

The Guidebook shows how to check resistance of the coolant temp. circuit at the ECU connector.  That will show you if the ECU is getting good information.

 

Once you run out of the simple checks, the best route is to get a multimeter and run through all of the electrical tests.  They don't take as long as you would think and when you're done you'll probably have found a few simple things to make better in addition to maybe finding the big problem.

 

If everything checks out then you can move on to the odd problems, like fuel pumps that are corroded and overheat after a few minutes of running.  Two of us have had those.

 

 

Ok thanks for the above post! Very helpful. I have quite a few years working on FI cars and especially the BOSCH systems, but all in BMW's and this is my first Z car. I did run through the checks today with a DVM and the big glaring problem was the "Thermotime Switch" on page 19 of the EFI book. It was supposed to have 740-940 Ohm resistance at the coolant temp today and it was around the six mega-ohm range. 

 

However, when I tried to get this part at the local parts store, then only had one thing listed as a "coolant temp switch". Now the diagram shows shows three different sensors screwed into the thermostat housing on this 78 280. One I take it the "Thermotime switch" than controls the cold start system, the other two I don't know. Any ideas? 

I have a picture of the one I purchased today, but can't seen to figure out how to upload to this site. I also have some screen captures of the tech manuals, but the same problem. 

 

Cheers, 

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Also,

Today with the 78, its about 25F today in western Oregon and the car started right up and idled for about 15 min. I could even rev her into the 3-4K range with no problem or hesitation. Then once she warmed up to around 120F(coolant) she started to stumble and misfire. Here are a couple questions I have and was hoping someone might be able to clear up.

1. on page 19(and 49) of the 78+ EFI bible is that Thermotime switch the same that is tested on page 79 of the same book?

2. would a malfunctioning Thermotime Switch/Coolant temperature sensor cause the symptoms I talked about above?

 

Thanks in advance!

 

PS: Does anybody know of a good parts source for this year of car? 

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Also,

Today with the 78, its about 25F today in western Oregon and the car started right up and idled for about 15 min. I could even rev her into the 3-4K range with no problem or hesitation. Then once she warmed up to around 120F(coolant) she started to stumble and misfire. Here are a couple questions I have and was hoping someone might be able to clear up.

1. on page 19(and 49) of the 78+ EFI bible is that Thermotime switch the same that is tested on page 79 of the same book?

2. would a malfunctioning Thermotime Switch/Coolant temperature sensor cause the symptoms I talked about above?

 

Thanks in advance!

 

PS: Does anybody know of a good parts source for this year of car? 

 

Your question 1: No they are not the same. Page 19 & 49 refer to the Thermotime temp sensor (for the Cold Start System circuit) and page 79 is a test for the temp. sensor for the ECU.

Page 64 has a goed overview of the two temperature circuits. (Pin 13 and Pin 21 on the ECU connector)

 

If you want to test the Thermotime circuit. It is on page 98 Test #3 - (3).

 

Poor connections are a big problem with these cars and very important in these old (analoge) systems. I replaced my connectors with aftermarket on the Injectors (for easy testing) and OEM on the Temp.sensors. See attachments

 

I don't have much info on the 78. Just about everything I have is based on the 77.

Here is a photo from AtlanticZ and a snapshot of the wiring for the 280Z 1978. Hope thats the right diagram.

 

Good luck with hunting it down.

Chas

post-25317-0-90241200-1420106146_thumb.j

post-25317-0-53701200-1420106225_thumb.j

post-25317-0-70837800-1420107979_thumb.j

post-25317-0-52648200-1420108006_thumb.j

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PS: Does anybody know of a good parts source for this year of car?

I find a lot of parts simply by trying nissan first them the aftermarket dealers.

A good nissan site is Courtesy Nissan:

http://www.courtesyparts.com/240z-260z-280z-parts-s30-1970-1978-c-7724.html

Aftermarket:

http://www.zzxdatsun.com/cat280z.php

https://www.rockauto.com/catalog/catalog.php

http://www.motorsportauto.com

http://www.blackdragonauto.com

Those are some of the common ones.

Here is a good site for the parts manual

http://www.carpartsmanual.com/datsunS30/DatsunZIndex.aspx

Chas

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+1 on corroded connectors - you might want to spend a couple hours and trace every wire int the harness, pull apart every connector, use some deoxit or other cleaner, some 400 grit paper, re-connect w/a little dielectric grease, unscrew every ground connection (some on manifold, some on chassis) and do the same. nothin' worse than chasing intermittencies and other electrical gremlins when you have a bad ground or crappy connection!

besides being a good way to set a baseline, it's a good exercise to get you familiar with the harness, it's parts, and prevent a bad connection that would have shown up in the future...

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also, if this hasn't already been stated, if you have a bunch of little problems, they can all add up and shut you down.

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