GPZ1100 with Old-Styl DFI Won't Start When Hot

Hi:

I have a 1981 GPZ1100 bike that I bought from the original owner last year and it was barely running, but after a lot of time and a decent chunk of change, I got it running this spring, and it runs well. However, after a 100+ mile ride last weekend, when the temperature had approached 100F, I got home, shut the bike off, and went in the house for a few minutes. I then came out to start the bike to put it in my garage, but it would only crank and not fire up, so I pushed it into the garage and let it sit for the week.

Last night, I took it back out and it fired up just fine, and I took it for an hour ride around my area, where it ran fine the whole time. But when I shut it off, and tried to start it a couple of minutes later, the same thing happened again. Cranking, but no firing. I waited every few minutes and tried to start it again, and each time I did that, it would try to start and run a little on some of the cylinders. After about a half hour of this, and the engine was still quite warm/hot, it started up and ran, though I never rode it.

Based upon the description of the problem above, what do you think is wrong? Since last year, I have replaced the complete ignition system with a Dyna system, new plugs, new fuel filter, cleaned the gas tank, checked all of the fuel system's components by the book - factory service manual, I had the injectors cleaned, checked the fuel pressure at idle and off-idle, and on and on. As I had said, I had gotten it to run properly at the beginning of the season, and was very happy with the bike, but now this.

I'm keeping it stock with the Bosch DFI, and I don't wish to go to carbs. I know, I'm a glutton for punishment.

What should I focus on to see where the problem is?

Thanks in advance for your assistance.

Marty

Your bike has the 2nd generation DFI with an air flow switch next to/under the airfilter.

Here's some more information on a replacement switch:

1980 KZ 1000 G1 (Z1 Classic)
I took this from the www.kzrider website.

below is a description with autos and part numbers for this throttle switch. ONLY COST $80.

This little switch has *profound* affects on the usability of the bike. Only 1 side of the 2-pole switch was intermittently bad, and it basically made the bike UNUSABLE.

I found the switch today at O'Reilly Auto Parts store here in Silicon Valley -- they used the matching autos to look it up in the O'Reilly computer in the store (using 'Kawasaki' or the Kaw part number was *not* useful, it had to be a car with the year/model or a part number for the switch).

The local O'Reilly store today looked it up for the 1979 Datsun 280zx and they HAD ONE IN STOCK. Put it on the bike, I'm gone on a 45-minute ride around the Valley!
NARY A HICKUP. Bike is fiiiiiine.

So for anyone else with this one-year-only Kz1000 "Z1 Classic", here are a few ways to find this switch:

1) 1979 Datsun 280zx "Throttle Valve Switch"

2) 1980 Datsun 200sx, find it at
Remartautoparts.com, with Remart part # TH114

3) "BECK ARNLEY 158-0492 Fuel Injector Throttle Switch" (NOTE: the 158-0492 is a 'master' part number apparently that most Auto parts stores can use to find all the vendors of this switch)

4) 1986 Nissan 300ZX Turbo "Throttle Position Sensor",
the part is mfg. by 'Nile'

If I were you, I'd buy one to have on hand if your bike acts up like this rider's did.

www.redlinecycle.com/Fuel%20Injection.html Some parts for the 1980 Kawasaki Kz1000 "G" model

Fuse And Fuse Holder Designations

1. The older Kawasaki’s use a glass tubed fuse with the designation of AGX 1” long. Most good auto parts stores can get them for you. They are ¼” in diameter.

2. The more common AGC is 1 ¼” long and may not fit the smaller fuse clips. Again, ¼” in diameter.

3. To clean and polish the fuse clips, I use a cotton swab(Q- Tip) and some Brasso metal cleaner or Turtle Wax Chrome Polish. I suppose any good metal polish would work.

4. These fuses can fail internally but look good, only by removing them from the clip and electrically continuity checking with either a self powered test light, or a multimeter set on OHMS can they be determined to be in good shape. I replace my bikes fuses every 6 months to a year.

5. A physical inspection of the metal end caps for tightness will tell you if the fuse is serviceable.

6. Most modern motorcycles are now using the automobile “Blade” style fuse with the designation of ATC or ATO.

7. The reduced sized “Mini” Blade style fuse holder uses the ATM size of fuses.

8. If the fuse and fuse holder overheat, it could soften or anneal the grip of the clip, it might require squeezing the clip to restore the tightness.

9. A list of where to purchase “Blade” style fuses and holders:

www.waytekwire.com order.waytekwire.com/productdetail2/M50/...20%20%20%208%20FUSE/

www.rallylights.com www.rallylights.com/detail.aspx?ID=765

www.delcity.net/store/6!way-fuse-blocks/p_10822.a_1

10. A source for the glass tubed AGX fuses:
www.boatownerswarehouse.com/browse.cfm/2,4986.html

The Dreaded Shorting/Intermittent Electrical Problem!


Here is the most basic method I know(Taken from www.kzrider.com by member Patton)

1. Charge your battery and have it load tested if you can. The floating ball hydrometer can be used to check the specific gravity of the charged cells in the battery.

2. Disconnect the Black lead from the (-) Battery terminal... or Red from the (+) Battery terminal, it does not matter which one. Just 1, not both!

3. Connect one of the following test setups in series with the Battery terminal and lead:
3.1 A 12 V light bulb,
3.2 A 12 V test light,
3.3 A 12 V test buzzer or,
3.4 A 12 V horn... you get the idea.

4. With the Ignition Switch OFF, go through your harness and wiggle the wires while looking/listening for the test setup to go on/start buzzing.

5.With the Ignition Switch ON, repeat the test except this time the looking/listening for the test setup to go off/stop buzzing.

6. Be prepared to open the Ignition switch and check/test for solder joint failure and or circuit board micro breaks (don't ask how I know this ).

7. Be prepared to pull the wires out of the Head Light to test for failures at or near the grommet.

8. Be prepared to open the harness at or near the Steering Neck for failures. This is where wires tend to exhibit fatigue due to repetitive movement.

9. Be prepared to open the left and right switch gear to search for rust and or broken parts. CAUTION: watch out for flying springs, ball bearings and stuff. Do indoors on White sheet (again don't ask ).

10. Be prepared to follow the heavy gauge wire from the Starter Solenoid (Relay) to the starter for bare wire exposure. Especially near bends and grommets.

11. If you can reproduce the fault symptom your are pretty much home free. Be prepare to find and repair/replace any internal wire breaks, insulation break downs, exposed wires, rubber grommet failures, etc. Often, shrink tubing will solve the problem temporarily until something better can be done.

12. I use a very good electrical contact cleaner/preservative called De-oxit made by Caig Labs in San Diego Ca. Their website is www.deoxit.com It can be purchased at Radio Shack and any other electronic supply store. I use it on all of my motorcycle’s electrical connectors , in my home entertainment center’s stereo patch cords and cordless phones charging cradles.

I would suspect the Engine Temp Sensor. Check it for resistance with an Ohm meter both hot and cold. Most sensors are built with 2 internal resistance ramps. One will do the extreme cold the other will do warm to extreme hot. The upper could have failed giving an open circuit.

While this is Not specific to your Kawasaki it has the basic info for testing a temp sensor through a heat range: www.ratwell.com/technical/TempSensorII.html
Your sensor should have a part # at the nut stamped into it. It may be a Bosch #.

Remember that the single wire type of temp sensor must be clean and tight in the mounting hole to get a good contact to Ground. As the varying resistance is between the terminal end and ground, a loose sensor will not give an accurate reading.

Kawasaki Fuel Injection Sensor Specs

Here's from my 1982 GPz1100 B2 factory shop manual(your bike is very similar to mine but your's does not have the throttle position sensor):

Air temperature sensor spec(probably the one on the air filter housing, or next to it).

Meter at ohms X 1K ohms ( I use ohms X 2K as it works on my meter)
Disconnect the wiring from the harness, one meter probe to one of the connector pins, the other on the last pin.

Should read 2.0K ohms to 3.0 K ohms at 68 F, if your meter won't read this, try the 20K ohm setting.

A footnote says this reading is true when sensor temperature is 20C (68F), 4.7 K ohms to 7.6 K ohms when 0 C (32 F) and 1.4 K ohms to 2.2 K ohms when 30 C (86 F).

Engine temperature sensor spec(between the #1 & #2 cylinders on the intake side):
Again, meter to 2K ohm settings, one meter lead to the push on terminal (remove the wire as it may give a false reading) and the other to a chassis ground(any Black with Yellow stripe wire is part of the ground circuit).

The readings will be the same as the air temperature sensor.

Guys,

Thanks for the replies. I'll check the cylinder temperature sensor. I know where it's at because I had it out last fall, and checked it while trying to figure out why it wouldn't run right last year. That turned out to be a rusty tank, and I fixed that.

Marty

If not already done, would assure valve clearances are within specs.

A too tight valve may result in loss of compression as the engine warms.

Good Fortune!

When this happens, can you hear the fuel pump cycle when you turn on the key?

As Patten suggested, if you haven't already, verify the valve lash clearances. If that's never been done, get that out of the way before you pull your hair out chasing a ghost.

If lash is good, I would duplicate the condition to get the engine hot, shut it off BUT try to immediately restart it. If it starts right back up again, turn if off, let it heat soak for a few minutes and then try to start it again....see what happens then.

Injectors mounted directly in the head like those EFI setups had, could be problematic sometimes when they got heat soaked.

The pump also should run if you remove the air filter and push the air gate open....

Guys:

Worked on it tonight, and here's what I did, and what happened:

Checked the engine temperature sensor and air flow meter per the factory service manual's specs, and everything checked out. I have a spare of each that I picked up over the winter and checked those too. They were within the factory resistance check specs also, so for the heck of it, I swapped those with the originals that came on the bike just in case. Mounting hole threads, cylinder head mounting surface, and connections for the engine temperature sensor were clean and tight.

I fired the bike up and rode it at high speed (70 - 80 MPH) for 40 miles straight with no problems, came home (I'm right off the highway) and shut it off. I tried to start it immediately, and it started fine and ran, but after 10-15 minutes, it would crank and not fire up. After 37 minutes, it started and ran, but I didn't take it for a ride. It revved in the driveway all right though.

The temperature tonight was around 85F.

I checked the valve clearances last fall, and they were all right, and I haven't put much more than 600 miles on it so far this year.

I owned one these same GPZ's many years ago, and I cannot recall it acting like this when the temperature was in the eighties, back in the eighties.

Would it be a good idea to take a hair dryer or heat gun to suggested electrical items to see if they'll act up when heated with either? As I had said earlier, I have replaced the complete ignition with Dynatek components (Dyna III ignition, Dyna green coils and Dyna wires, and NGK plugs).

Could a tight valve or two, really throw off the DFI system this much, and have it exhibit this type of behavior? I hate to go back in there to check them again, but again, I picked up a pair of '83-'84 GPZ cams that I could put in during the effort. I also have a newer Walbro fuel pump and Bosch adjustable fuel pressure regulator that could be thrown in for good measure. However, I was looking to do some or all of that after this riding season.

I'm open to suggestions for checking other things.

Thanks again.
Marty

It might be the ignition pick up(Pulsing coils) getting hot causing this problem:

Ohm Checking Pickup(Pulsing) Coils

The pickup coils on the Kawasaki’s with the factory supplied electronic ignition can sometimes fail or become intermittent due to heat and vibration.

1.Trace back from where the pick up coils are mounted,(under a right side CD sized cover) locate and disconnect a small 4 pin connector. Using a multi-meter set on OHMS and range of 2K, check between the BLUE and BLACK wires(#1 and #4 sparkplug wires) for between 360- 540 OHMS.

2.For #2 and #3 sparkplugs the wire colors will be YELLOW and RED, again 360-540 OHMS. The 550’s,650’s & 750’s may be backwards to the Z1’s,Kz900’s,Kz1000’s & Kz1100’s.

3.If the pickup coils are suspect of failing due to heat, they can be stressed using a hair dryer without the need of the engine running.

4.A replacement set of pickup coils might be obtained from a dealer who serviced the police Kawasaki’s.

5. If replacement pickup coils are not available, your next choice would be to order a Dyna “S” electronic ignition system from www.z1enterprises.com It replaces the IC igniter with a smaller module located where the mechanical ignition advancer was mounted.

6. Checking with Kawasaki.com website has determined that the Pick up(pulsing) coils are available . The pulsing coil # is 59026-1133 and replaces the older # 1002, 1012 which were used from the MKII motors until the 2005 P24.

7.Check the small 4 pin connector that the pickup coils connect to for corrosion/loose pins too.




How old's the ignition coils?

Ignition Coil Primary And Secondary Wiring

Ignition coils on the 80’s Kz1000,Kz1100’s and Gpz1100’s are wired the same, that is as you sit on the bike, the LEFT ignition coil primary(small wires) are two wires, RED and BLACK. The secondary (or sparkplug wires) go to #1 and #4 sparkplugs(your primary wiring may be different).

The cylinders are numbered left to right as you sit on the seat; #1,#2,#3, and #4.

For the RIGHT ignition coil, the primary wires, again are two wires, RED and GREEN, with the secondary going to #2 and #3.

The RED wire gets it’s voltage from the run/stop switch on the right handlebar switch pod. Your primary wiring may have a different color.

The BLACK and GREEN wires connect to the IC Igniter(if the bike has the Kawasaki supplied electronic ignition) it actually gives the coils their grounds to fire the sparkplugs.

Primary(small wires) side of the coils will read between 1.8 to 3.0 ohms.

Secondary(sparkplug wire ports)side of the coil will read between 10.4K to 15.6K ohms. These ports are wired together, so it makes no difference which is used, as long as the correct coil to sparkplug configuration is followed.

The sparkplug caps should read 5K OHMS, any higher, or a reading of infinity means new caps should be ordered.

To stress the ignition coils, take a hair dryer, heat the coils and see if the ohm readings change from cold to hot . If they do, it’s probably time to buy new coils.

---

Keep in mind, the wiring is reversed for the 550’s 650‘s and 750‘s, that is the RIGHT coil primary will be two wires, RED and BLACK with the secondary(sparkplugs) going to #1 and #4.

The LEFT coils primary wiring would be again two wires, RED and GREEN, with the secondary(sparkplugs) going to #2 and #3.

These engines have what is known as a “Wasted Spark” that is, a sparkplug will fire during an exhaust stroke. It does no damage and many other motorcycle engines have this design.

If the pick up coils test good, possibly the IC Igniter is going out. "Loudhvx" here, has made a replacement using off the shelf GM electronic modules.